diff --git a/src/main/java/org/openrewrite/staticanalysis/MinimumSwitchCases.java b/src/main/java/org/openrewrite/staticanalysis/MinimumSwitchCases.java
index c2aa5a339c..7c18c0a0fd 100644
--- a/src/main/java/org/openrewrite/staticanalysis/MinimumSwitchCases.java
+++ b/src/main/java/org/openrewrite/staticanalysis/MinimumSwitchCases.java
@@ -31,10 +31,7 @@
 import org.openrewrite.marker.Markers;
 import org.openrewrite.staticanalysis.csharp.CSharpFileChecker;
 
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Set;
-import java.util.UUID;
+import java.util.*;
 
 import static java.util.Collections.singleton;
 import static java.util.Collections.singletonList;
@@ -192,6 +189,26 @@ public J visitSwitch(J.Switch switch_, ExecutionContext ctx) {
                             }
                         }
 
+                        Map<String, J.VariableDeclarations> firstCaseDeclarations = new JavaIsoVisitor<Map<String, J.VariableDeclarations>>() {
+                            @Override
+                            public J.VariableDeclarations visitVariableDeclarations(J.VariableDeclarations multiVariable, Map<String, J.VariableDeclarations> variableDeclarations) {
+                                for (J.VariableDeclarations.NamedVariable var_ : multiVariable.getVariables()) {
+                                    variableDeclarations.put(var_.getSimpleName(), multiVariable.withVariables(ListUtils.filter(multiVariable.getVariables(), v -> v == var_)));
+                                }
+                                return multiVariable;
+                            }
+
+                            @Override
+                            public J.Block visitBlock(J.Block block, Map<String, J.VariableDeclarations> variableDeclarations) {
+                                for (Statement statement : block.getStatements()) {
+                                    if (statement instanceof J.VariableDeclarations) {
+                                        visitVariableDeclarations((J.VariableDeclarations) statement, variableDeclarations);
+                                    }
+                                }
+                                return block;
+                            }
+                        }.reduce(cases[0], new HashMap<>());
+
                         // move first case to "if"
                         List<Statement> thenStatements = getStatements(cases[0]);
 
@@ -201,13 +218,36 @@ public J visitSwitch(J.Switch switch_, ExecutionContext ctx) {
                         // move second case to "else"
                         if (cases[1] != null) {
                             assert generatedIf.getElsePart() != null;
+                            JavaVisitor<Map<String, J.VariableDeclarations>> firstAssignmentAsDeclarationVisitor = new JavaVisitor<Map<String, J.VariableDeclarations>>() {
+
+                                @Override
+                                public J visitStatement(Statement statement, Map<String, J.VariableDeclarations> stringVariableDeclarationsMap) {
+                                    if (statement instanceof J.Assignment) {
+                                        return visitAssignment((J.Assignment) statement, stringVariableDeclarationsMap);
+                                    }
+                                    return super.visitStatement(statement, stringVariableDeclarationsMap);
+                                }
+
+                                @Override
+                                public J visitAssignment(J.Assignment assignment, Map<String, J.VariableDeclarations> firstCaseDeclarations) {
+                                    if (assignment.getVariable() instanceof J.Identifier) {
+                                        String varName = ((J.Identifier) assignment.getVariable()).getSimpleName();
+                                        if (firstCaseDeclarations.containsKey(varName)) {
+                                            J.VariableDeclarations originalDecl = firstCaseDeclarations.remove(varName);
+                                            return originalDecl.withVariables(ListUtils.map(originalDecl.getVariables(), v -> v.withInitializer(assignment.getAssignment())));
+                                        }
+                                    }
+                                    return super.visitAssignment(assignment, firstCaseDeclarations);
+                                }
+                            };
+
                             if (isDefault(cases[1])) {
                                 generatedIf = generatedIf.withElsePart(generatedIf.getElsePart().withBody(((J.Block) generatedIf.getElsePart().getBody()).withStatements(ListUtils.map(getStatements(cases[1]),
-                                        s -> s instanceof J.Break ? null : s))));
+                                        s -> s instanceof J.Break || s == null ? null : (Statement) firstAssignmentAsDeclarationVisitor.visitStatement(s, firstCaseDeclarations)))));
                             } else {
                                 J.If elseIf = (J.If) generatedIf.getElsePart().getBody();
                                 generatedIf = generatedIf.withElsePart(generatedIf.getElsePart().withBody(elseIf.withThenPart(((J.Block) elseIf.getThenPart()).withStatements(ListUtils.map(getStatements(cases[1]),
-                                        s -> s instanceof J.Break ? null : s)))));
+                                        s -> s instanceof J.Break || s == null ? null : (Statement) firstAssignmentAsDeclarationVisitor.visitStatement(s, firstCaseDeclarations))))));
                             }
                         }
 
@@ -250,7 +290,6 @@ private boolean switchesOnEnum(J.Switch switch_) {
                 return selectorType instanceof JavaType.Class &&
                        ((JavaType.Class) selectorType).getKind() == JavaType.Class.Kind.Enum;
             }
-
         });
     }
 
diff --git a/src/test/java/org/openrewrite/staticanalysis/MinimumSwitchCasesTest.java b/src/test/java/org/openrewrite/staticanalysis/MinimumSwitchCasesTest.java
index 0a37ff4e6c..acc5808466 100644
--- a/src/test/java/org/openrewrite/staticanalysis/MinimumSwitchCasesTest.java
+++ b/src/test/java/org/openrewrite/staticanalysis/MinimumSwitchCasesTest.java
@@ -887,4 +887,108 @@ void doSomethingElse() {}
           )
         );
     }
+
+    @Issue("https://github.com/openrewrite/rewrite-static-analysis/issues/687")
+    @Test
+    void variableRedeclarationInNewBlocks() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              class Test {
+                  int someInt;
+                  void test() {
+                      switch (someInt) {
+                          case 1:
+                              String data = getSomeString();
+                              doThingOneWith(data);
+                              break;
+                          case 2:
+                              data = getSomeOtherString();
+                              doThingTwoWith(data);
+                              break;
+                      }
+                  }
+                  String getSomeString() { return "one"; }
+                  String getSomeOtherString() { return "two"; }
+                  void doThingOneWith(String data) {}
+                  void doThingTwoWith(String data) {}
+              }
+              """,
+            """
+              class Test {
+                  int someInt;
+                  void test() {
+                      if (someInt == 1) {
+                          String data = getSomeString();
+                          doThingOneWith(data);
+                      } else if (someInt == 2) {
+                          String data = getSomeOtherString();
+                          doThingTwoWith(data);
+                      }
+                  }
+                  String getSomeString() { return "one"; }
+                  String getSomeOtherString() { return "two"; }
+                  void doThingOneWith(String data) {}
+                  void doThingTwoWith(String data) {}
+              }
+              """
+          )
+        );
+    }
+
+    @Issue("https://github.com/openrewrite/rewrite-static-analysis/issues/687")
+    @Test
+    void MultipleVariableRedeclarationInNewBlocks() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              class Test {
+                  int someInt;
+                  void test() {
+                      switch (someInt) {
+                          case 1:
+                              String data = getSomeString(), otherString = getSomeString();
+                              doThingOneWith(data);
+                              doThingOneWith(otherString);
+                              break;
+                          case 2:
+                              data = getSomeOtherString();
+                              otherString = getSomeOtherString();
+                              doThingTwoWith(data);
+                              doThingTwoWith(otherString);
+                              break;
+                      }
+                  }
+                  String getSomeString() { return "one"; }
+                  String getSomeOtherString() { return "two"; }
+                  void doThingOneWith(String data) {}
+                  void doThingTwoWith(String data) {}
+              }
+              """,
+            """
+              class Test {
+                  int someInt;
+                  void test() {
+                      if (someInt == 1) {
+                          String data = getSomeString(), otherString = getSomeString();
+                          doThingOneWith(data);
+                          doThingOneWith(otherString);
+                      } else if (someInt == 2) {
+                          String data = getSomeOtherString();
+                          String otherString = getSomeOtherString();
+                          doThingTwoWith(data);
+                          doThingTwoWith(otherString);
+                      }
+                  }
+                  String getSomeString() { return "one"; }
+                  String getSomeOtherString() { return "two"; }
+                  void doThingOneWith(String data) {}
+                  void doThingTwoWith(String data) {}
+              }
+              """
+          )
+        );
+    }
 }