diff --git a/sqlite3.go b/sqlite3.go
index 15c7003..69a2a9b 100644
--- a/sqlite3.go
+++ b/sqlite3.go
@@ -29,10 +29,6 @@ struct tm* _localtime32(const __time32_t *tm) {
 # define SQLITE_OPEN_FULLMUTEX 0
 #endif
 
-#ifndef SQLITE_THREADSAFE
-# define SQLITE_THREADSAFE
-#endif
-
 static int
 _sqlite3_open_v2(const char *filename, sqlite3 **ppDb, int flags, const char *zVfs) {
 #ifdef SQLITE_OPEN_URI
diff --git a/sqlite3_other.go b/sqlite3_other.go
index c87c01f..54b6c7a 100644
--- a/sqlite3_other.go
+++ b/sqlite3_other.go
@@ -9,6 +9,6 @@ package sqlite3
 /*
 #cgo CFLAGS: -I.
 #cgo linux LDFLAGS: -ldl
-#cgo CFLAGS: -DSQLITE_ENABLE_RTREE
+#cgo CFLAGS: -DSQLITE_ENABLE_RTREE -DSQLITE_THREADSAFE
 */
 import "C"
diff --git a/sqlite3_windows.go b/sqlite3_windows.go
index 9c47124..1b339a0 100644
--- a/sqlite3_windows.go
+++ b/sqlite3_windows.go
@@ -8,6 +8,6 @@ package sqlite3
 /*
 #cgo CFLAGS: -I. -fno-stack-check -fno-stack-protector -mno-stack-arg-probe
 #cgo LDFLAGS: -lmingwex -lmingw32
-#cgo CFLAGS: -DSQLITE_ENABLE_RTREE
+#cgo CFLAGS: -DSQLITE_ENABLE_RTREE -DSQLITE_THREADSAFE
 */
 import "C"