diff --git a/src/isolate.h b/src/isolate.h
index 96e044596d..a998d4dc71 100644
--- a/src/isolate.h
+++ b/src/isolate.h
@@ -1232,7 +1232,6 @@ class Isolate {
   Counters* counters_;
   CodeRange* code_range_;
   base::RecursiveMutex break_access_;
-  base::Atomic32 debugger_initialized_;
   Logger* logger_;
   StackGuard stack_guard_;
   StatsTable* stats_table_;