diff --git a/README.md b/README.md
index 9d13012..2ee838f 100644
--- a/README.md
+++ b/README.md
@@ -76,7 +76,7 @@ Read a buffer with specified length
 ### nextString(length, [encoding])
 Read next length of bytes as String, encoding default is 'utf8'
 
-### next(Int8|UInt8)\[(Int16|UInt16|Int32|UInt32|Float|Double)(LE|BE)\]()
+### next(Int8|UInt8)\[(Int16|UInt16|Int32|UInt32|BigInt64|BigUInt64|Float|Double)(LE|BE)\]()
 Read next bytes as given types, the value is just as the same format Buffer in nodejs doc.
 
 ## License
diff --git a/index.js b/index.js
index dacc30b..af52ad0 100644
--- a/index.js
+++ b/index.js
@@ -92,6 +92,8 @@ MAKE_NEXT_READER_BOTH('UInt16', 2);
 MAKE_NEXT_READER_BOTH('Int16', 2);
 MAKE_NEXT_READER_BOTH('UInt32', 4);
 MAKE_NEXT_READER_BOTH('Int32', 4);
+MAKE_NEXT_READER_BOTH('BigUInt64', 8);
+MAKE_NEXT_READER_BOTH('BigInt64', 8);
 MAKE_NEXT_READER_BOTH('Float', 4);
 MAKE_NEXT_READER_BOTH('Double', 8);