diff --git a/src/expr.c b/src/expr.c
index 2d67d8d6..382eec08 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -1145,7 +1145,9 @@ static int UnMinus(void)
 {
     Value *v = &ValStack[ValStackPtr-1];
     if (v->type != INT_TYPE) return E_BAD_TYPE;
+    int old = v->v.val;
     v->v.val = -v->v.val;
+    if (_private_unminus_overflow(old, v->v.val)) return E_2HIGH;
     return OK;
 }
 
diff --git a/src/expr.h b/src/expr.h
index f721b17b..1c891631 100644
--- a/src/expr.h
+++ b/src/expr.h
@@ -57,3 +57,4 @@ else \
 extern int _private_div(int a, int b);
 extern int _private_add_overflow(int result, int b, int old);
 extern int _private_sub_overflow(int result, int b, int old);
+extern int _private_unminus_overflow(int a, int b);
diff --git a/src/utils.c b/src/utils.c
index 6409da36..0993b4e1 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -140,3 +140,9 @@ int _private_sub_overflow(int result, int b, int old)
     return 0;
 }
 
+int _private_unminus_overflow(int a, int b)
+{
+    if (a > 0 && b > 0) return 1;
+    if (a < 0 && b < 0) return 1;
+    return 0;
+}