diff --git a/src/draco/io/stdio_file_reader.cc b/src/draco/io/stdio_file_reader.cc
index 560c3e9..09ce0fb 100644
--- a/src/draco/io/stdio_file_reader.cc
+++ b/src/draco/io/stdio_file_reader.cc
@@ -87,7 +87,13 @@ size_t StdioFileReader::GetFileSize() {
     return false;
   }
 
+  
+
+  #if defined(_WIN64)
+  const size_t file_size = static_cast<size_t>(_ftelli64(file_));
+  #else
   const size_t file_size = static_cast<size_t>(ftell(file_));
+  #endif
   rewind(file_);
 
   return file_size;