diff --git a/src/main/java/org/elasticsearch/watcher/trigger/schedule/IntervalSchedule.java b/src/main/java/org/elasticsearch/watcher/trigger/schedule/IntervalSchedule.java
index 4fe3eeae689..95ba8bac2f2 100644
--- a/src/main/java/org/elasticsearch/watcher/trigger/schedule/IntervalSchedule.java
+++ b/src/main/java/org/elasticsearch/watcher/trigger/schedule/IntervalSchedule.java
@@ -174,7 +174,7 @@ public class IntervalSchedule implements Schedule {
 
             Interval interval = (Interval) o;
 
-            if (unit.millis(duration) != interval.unit.millis(duration)) return false;
+            if (unit.millis(duration) != interval.unit.millis(interval.duration)) return false;
 
             return true;
         }
diff --git a/src/main/java/org/elasticsearch/watcher/trigger/schedule/engine/SchedulerScheduleTriggerEngine.java b/src/main/java/org/elasticsearch/watcher/trigger/schedule/engine/SchedulerScheduleTriggerEngine.java
index 64e50b3e2f6..29aab082a6a 100644
--- a/src/main/java/org/elasticsearch/watcher/trigger/schedule/engine/SchedulerScheduleTriggerEngine.java
+++ b/src/main/java/org/elasticsearch/watcher/trigger/schedule/engine/SchedulerScheduleTriggerEngine.java
@@ -167,7 +167,13 @@ public class SchedulerScheduleTriggerEngine extends ScheduleTriggerEngine {
             ActiveSchedule[] newSchedules = new ActiveSchedule[schedules.length];
             ImmutableMap.Builder<String, ActiveSchedule> builder = ImmutableMap.builder();
             for (int i = 0; i < schedules.length; i++) {
-                ActiveSchedule sched = schedules[i].name.equals(schedule.name) ? schedule : schedules[i];
+                final ActiveSchedule sched;
+                if (schedules[i].name.equals(schedule.name)) {
+                    sched = schedule;
+                    schedules[i].cancel();
+                } else {
+                    sched = schedules[i];
+                }
                 newSchedules[i] = sched;
                 builder.put(sched.name, sched);
             }
diff --git a/src/test/java/org/elasticsearch/watcher/test/integration/BasicWatcherTests.java b/src/test/java/org/elasticsearch/watcher/test/integration/BasicWatcherTests.java
index c473b5ef3c8..76764334234 100644
--- a/src/test/java/org/elasticsearch/watcher/test/integration/BasicWatcherTests.java
+++ b/src/test/java/org/elasticsearch/watcher/test/integration/BasicWatcherTests.java
@@ -5,10 +5,12 @@
  */
 package org.elasticsearch.watcher.test.integration;
 
+import org.apache.lucene.util.LuceneTestCase;
 import org.elasticsearch.action.search.SearchRequest;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.action.support.IndicesOptions;
 import org.elasticsearch.common.joda.time.DateTime;
+import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.script.ScriptService;
@@ -248,6 +250,42 @@ public class BasicWatcherTests extends AbstractWatcherIntegrationTests {
         assertThat(count, equalTo(findNumberOfPerformedActions("_name")));
     }
 
+    @Test
+    @LuceneTestCase.Slow
+    public void testModifyWatchWithSameUnit() throws Exception {
+        if (timeWarped()) {
+            logger.info("Skipping testModifyWatches_ because timewarp is enabled");
+            return;
+        }
+
+        WatchSourceBuilder source = watchBuilder()
+                .trigger(schedule(interval("1s")))
+                .input(simpleInput("key", "value"))
+                .throttlePeriod(TimeValue.timeValueSeconds(0))
+                .addAction("_id", loggingAction("hello {{ctx.watcher_id}}!"));
+        watcherClient().preparePutWatch("_name")
+                .setSource(source)
+                .get();
+
+        Thread.sleep(5000);
+        assertWatchWithMinimumPerformedActionsCount("_name", 5, false);
+
+        source = watchBuilder()
+                .trigger(schedule(interval("100s")))
+                .throttlePeriod(TimeValue.timeValueSeconds(0))
+                .input(simpleInput("key", "value"))
+                .addAction("_id", loggingAction("hello {{ctx.watcher_id}}!"));
+        watcherClient().preparePutWatch("_name")
+                .setSource(source)
+                .get();
+
+        // Wait one second to be sure that the scheduler engine has executed any previous job instance of the watch
+        Thread.sleep(1000);
+        long before = historyRecordsCount("_name");
+        Thread.sleep(5000);
+        assertThat("Watch has been updated to 100s interval, so no new records should have been added.", historyRecordsCount("_name"), equalTo(before));
+    }
+
     @Test
     public void testConditionSearchWithSource() throws Exception {
         String variable = randomFrom("ctx.execution_time", "ctx.trigger.scheduled_time", "ctx.trigger.triggered_time");