diff --git a/core/src/main/java/org/springframework/security/acls/domain/AclImpl.java b/core/src/main/java/org/springframework/security/acls/domain/AclImpl.java
index 7a3807c501..450fc8d58d 100644
--- a/core/src/main/java/org/springframework/security/acls/domain/AclImpl.java
+++ b/core/src/main/java/org/springframework/security/acls/domain/AclImpl.java
@@ -380,7 +380,7 @@ public class AclImpl implements Acl, MutableAcl, AuditableAcl, OwnershipAcl {
         synchronized (aces) {
             int offset = findAceOffset(aceId);
 
-            if (offset == 1) {
+            if (offset == -1) {
                 throw new NotFoundException("Requested ACE ID not found");
             }
 
@@ -395,7 +395,7 @@ public class AclImpl implements Acl, MutableAcl, AuditableAcl, OwnershipAcl {
         synchronized (aces) {
             int offset = findAceOffset(aceId);
 
-            if (offset == 1) {
+            if (offset == -1) {
                 throw new NotFoundException("Requested ACE ID not found");
             }