diff --git a/src/runtime/c/pgf/db.cxx b/src/runtime/c/pgf/db.cxx
index 92f48c001..ada843340 100644
--- a/src/runtime/c/pgf/db.cxx
+++ b/src/runtime/c/pgf/db.cxx
@@ -45,10 +45,15 @@ int last_error_to_errno()
 }
 #endif
 
+#if defined(_MSC_VER)
+PGF_INTERNAL __declspec( thread ) unsigned char* current_base = NULL;
+PGF_INTERNAL __declspec( thread ) PgfDB* current_db = NULL;
+PGF_INTERNAL __declspec( thread ) DB_scope *last_db_scope = NULL;
+#else
 PGF_INTERNAL __thread unsigned char* current_base __attribute__((tls_model("initial-exec"))) = NULL;
 PGF_INTERNAL __thread PgfDB* current_db __attribute__((tls_model("initial-exec"))) = NULL;
 PGF_INTERNAL __thread DB_scope *last_db_scope __attribute__((tls_model("initial-exec"))) = NULL;
-
+#endif
 
 #define ptr(T,o) ((T*) (base + (o)))
 
diff --git a/src/runtime/c/pgf/db.h b/src/runtime/c/pgf/db.h
index c6b1162b0..c593ea9ba 100644
--- a/src/runtime/c/pgf/db.h
+++ b/src/runtime/c/pgf/db.h
@@ -5,8 +5,13 @@
 
 class PgfDB;
 
+#if defined(_MSC_VER)
+extern PGF_INTERNAL_DECL __declspec( thread ) unsigned char* current_base;
+extern PGF_INTERNAL_DECL __declspec( thread ) PgfDB*         current_db;
+#else
 extern PGF_INTERNAL_DECL __thread unsigned char* current_base __attribute__((tls_model("initial-exec")));
 extern PGF_INTERNAL_DECL __thread PgfDB*         current_db   __attribute__((tls_model("initial-exec")));
+#endif
 
 struct block_descr;
 struct malloc_state;