diff --git a/ServiceScan.SourceGenerator.Tests/AddServicesTests.cs b/ServiceScan.SourceGenerator.Tests/AddServicesTests.cs
index 8014d2d..a9872d8 100644
--- a/ServiceScan.SourceGenerator.Tests/AddServicesTests.cs
+++ b/ServiceScan.SourceGenerator.Tests/AddServicesTests.cs
@@ -187,6 +187,62 @@ public class MyStringService : IService<string> { }
         Assert.Equal(Sources.GetMethodImplementation(registrations), results.GeneratedTrees[1].ToString());
     }
 
+    [Fact]
+    public void AddServicesAssignableToOpenGenericInterface_WithMultipleInterfaces()
+    {
+        var attribute = $"[GenerateServiceRegistrations(AssignableTo = typeof(IService<>))]";
+
+        var compilation = CreateCompilation(
+            Sources.MethodWithAttribute(attribute),
+            """
+            namespace GeneratorTests;
+
+            public interface IService<T> { }
+            public interface IOtherInterface { }
+            public class MyIntAndStringService : IService<int>, IService<string>, IOtherInterface { }
+            """);
+
+        var results = CSharpGeneratorDriver
+            .Create(_generator)
+            .RunGenerators(compilation)
+            .GetRunResult();
+
+        var registrations = $"""
+            return services
+                .AddTransient<global::GeneratorTests.IService<int>, global::GeneratorTests.MyIntAndStringService>()
+                .AddTransient<global::GeneratorTests.IService<string>, global::GeneratorTests.MyIntAndStringService>();
+            """;
+        Assert.Equal(Sources.GetMethodImplementation(registrations), results.GeneratedTrees[1].ToString());
+    }
+
+    [Fact]
+    public void AddServicesAssignableToOpenGenericInterface_WithMultipleInterfaces_AsSelfAndAsImplementedInterfaces()
+    {
+        var attribute = $"[GenerateServiceRegistrations(AssignableTo = typeof(IService<>), AsSelf = true, AsImplementedInterfaces = true, Lifetime = ServiceLifetime.Singleton)]";
+
+        var compilation = CreateCompilation(
+            Sources.MethodWithAttribute(attribute),
+            """
+            namespace GeneratorTests;
+
+            public interface IService<T> { }
+            public class MyIntAndStringService : IService<int>, IService<string> { }
+            """);
+
+        var results = CSharpGeneratorDriver
+            .Create(_generator)
+            .RunGenerators(compilation)
+            .GetRunResult();
+
+        var registrations = $"""
+            return services
+                .AddSingleton<global::GeneratorTests.MyIntAndStringService, global::GeneratorTests.MyIntAndStringService>()
+                .AddSingleton<global::GeneratorTests.IService<int>>(s => s.GetRequiredService<global::GeneratorTests.MyIntAndStringService>())
+                .AddSingleton<global::GeneratorTests.IService<string>>(s => s.GetRequiredService<global::GeneratorTests.MyIntAndStringService>());
+            """;
+        Assert.Equal(Sources.GetMethodImplementation(registrations), results.GeneratedTrees[1].ToString());
+    }
+
     [Fact]
     public void AddServicesAssignableToClosedGenericInterface()
     {
@@ -808,7 +864,7 @@ public class InterfacelessService {}
     }
 
     [Fact]
-    public void AddServicesBothAsSelfAndAsImplementedInterfaces()
+    public void AddServicesBothAsSelfAndAsImplementedInterfaces_InterfacesAreForwardedToSelfRegistration()
     {
         var attribute = """
             [GenerateServiceRegistrations(
diff --git a/ServiceScan.SourceGenerator/DependencyInjectionGenerator.FilterTypes.cs b/ServiceScan.SourceGenerator/DependencyInjectionGenerator.FilterTypes.cs
index f2a79a6..65960a0 100644
--- a/ServiceScan.SourceGenerator/DependencyInjectionGenerator.FilterTypes.cs
+++ b/ServiceScan.SourceGenerator/DependencyInjectionGenerator.FilterTypes.cs
@@ -10,7 +10,7 @@ namespace ServiceScan.SourceGenerator;
 
 public partial class DependencyInjectionGenerator
 {
-    private static IEnumerable<(INamedTypeSymbol Type, INamedTypeSymbol? MatchedAssignableType)> FilterTypes
+    private static IEnumerable<(INamedTypeSymbol Type, INamedTypeSymbol[]? MatchedAssignableTypes)> FilterTypes
         (Compilation compilation, AttributeModel attribute, INamedTypeSymbol containingType)
     {
         var assemblies = GetAssembliesToScan(compilation, attribute, containingType);
@@ -72,19 +72,19 @@ public partial class DependencyInjectionGenerator
             if (excludeAssignableToType != null && IsAssignableTo(type, excludeAssignableToType, out _))
                 continue;
 
-            INamedTypeSymbol matchedType = null;
-            if (assignableToType != null && !IsAssignableTo(type, assignableToType, out matchedType))
+            INamedTypeSymbol[] matchedTypes = null;
+            if (assignableToType != null && !IsAssignableTo(type, assignableToType, out matchedTypes))
                 continue;
 
-            yield return (type, matchedType);
+            yield return (type, matchedTypes);
         }
     }
 
-    private static bool IsAssignableTo(INamedTypeSymbol type, INamedTypeSymbol assignableTo, out INamedTypeSymbol? matchedType)
+    private static bool IsAssignableTo(INamedTypeSymbol type, INamedTypeSymbol assignableTo, out INamedTypeSymbol[]? matchedTypes)
     {
         if (SymbolEqualityComparer.Default.Equals(type, assignableTo))
         {
-            matchedType = type;
+            matchedTypes = [type];
             return true;
         }
 
@@ -92,9 +92,11 @@ private static bool IsAssignableTo(INamedTypeSymbol type, INamedTypeSymbol assig
         {
             if (assignableTo.TypeKind == TypeKind.Interface)
             {
-                var matchingInterface = type.AllInterfaces.FirstOrDefault(i => i.IsGenericType && SymbolEqualityComparer.Default.Equals(i.OriginalDefinition, assignableTo));
-                matchedType = matchingInterface;
-                return matchingInterface != null;
+                matchedTypes = type.AllInterfaces
+                    .Where(i => i.IsGenericType && SymbolEqualityComparer.Default.Equals(i.OriginalDefinition, assignableTo))
+                    .ToArray();
+
+                return matchedTypes.Length > 0;
             }
 
             var baseType = type.BaseType;
@@ -102,7 +104,7 @@ private static bool IsAssignableTo(INamedTypeSymbol type, INamedTypeSymbol assig
             {
                 if (baseType.IsGenericType && SymbolEqualityComparer.Default.Equals(baseType.OriginalDefinition, assignableTo))
                 {
-                    matchedType = baseType;
+                    matchedTypes = [baseType];
                     return true;
                 }
 
@@ -113,7 +115,7 @@ private static bool IsAssignableTo(INamedTypeSymbol type, INamedTypeSymbol assig
         {
             if (assignableTo.TypeKind == TypeKind.Interface)
             {
-                matchedType = assignableTo;
+                matchedTypes = [assignableTo];
                 return type.AllInterfaces.Contains(assignableTo, SymbolEqualityComparer.Default);
             }
 
@@ -122,7 +124,7 @@ private static bool IsAssignableTo(INamedTypeSymbol type, INamedTypeSymbol assig
             {
                 if (SymbolEqualityComparer.Default.Equals(baseType, assignableTo))
                 {
-                    matchedType = baseType;
+                    matchedTypes = [baseType];
                     return true;
                 }
 
@@ -130,7 +132,7 @@ private static bool IsAssignableTo(INamedTypeSymbol type, INamedTypeSymbol assig
             }
         }
 
-        matchedType = null;
+        matchedTypes = null;
         return false;
     }
 
diff --git a/ServiceScan.SourceGenerator/DependencyInjectionGenerator.FindServicesToRegister.cs b/ServiceScan.SourceGenerator/DependencyInjectionGenerator.FindServicesToRegister.cs
index b0eb81c..c47cfa0 100644
--- a/ServiceScan.SourceGenerator/DependencyInjectionGenerator.FindServicesToRegister.cs
+++ b/ServiceScan.SourceGenerator/DependencyInjectionGenerator.FindServicesToRegister.cs
@@ -31,7 +31,7 @@ private static DiagnosticModel<MethodImplementationModel> FindServicesToRegister
         {
             bool typesFound = false;
 
-            foreach (var (implementationType, matchedType) in FilterTypes(compilation, attribute, containingType))
+            foreach (var (implementationType, matchedTypes) in FilterTypes(compilation, attribute, containingType))
             {
                 typesFound = true;
 
@@ -46,7 +46,7 @@ private static DiagnosticModel<MethodImplementationModel> FindServicesToRegister
                         (true, true) => new[] { implementationType }.Concat(GetSuitableInterfaces(implementationType)),
                         (false, true) => GetSuitableInterfaces(implementationType),
                         (true, false) => [implementationType],
-                        _ => [matchedType ?? implementationType]
+                        _ => matchedTypes ?? [implementationType]
                     };
 
                     foreach (var serviceType in serviceTypes)