diff --git a/core/src/main/scala/cats/instances/sortedMap.scala b/core/src/main/scala/cats/instances/sortedMap.scala
index c4da92a8dee..afa4a52ae27 100644
--- a/core/src/main/scala/cats/instances/sortedMap.scala
+++ b/core/src/main/scala/cats/instances/sortedMap.scala
@@ -6,7 +6,6 @@ import cats.kernel.instances.StaticMethods
 
 import scala.annotation.tailrec
 import scala.collection.immutable.SortedMap
-import scala.collection.mutable
 
 trait SortedMapInstances extends SortedMapInstances1 {
 
@@ -159,15 +158,4 @@ class SortedMapMonoid[K, V](implicit V: Semigroup[V], O: Order[K]) extends Monoi
       }
     }
 
-  override def combineAll(xss: TraversableOnce[SortedMap[K, V]]): SortedMap[K, V] = {
-    val acc = mutable.SortedMap.empty[K, V](O.toOrdering)
-    xss.foreach { m =>
-      val it = m.iterator
-      while (it.hasNext) {
-        val (k, v) = it.next
-        acc(k) = Semigroup.maybeCombine(acc.get(k), v)
-      }
-    }
-    SortedMap.empty[K, V](O.toOrdering) ++ acc
-  }
 }
diff --git a/tests/src/test/scala/cats/tests/SortedMapTests.scala b/tests/src/test/scala/cats/tests/SortedMapTests.scala
index 0f6d068c789..e0fbc81c0e7 100644
--- a/tests/src/test/scala/cats/tests/SortedMapTests.scala
+++ b/tests/src/test/scala/cats/tests/SortedMapTests.scala
@@ -26,7 +26,7 @@ class SortedMapTests extends CatsSuite {
     }
   }
 
-  checkAll("Hash[Map[Int, String]]" , HashLawTests[Map[Int, String]].hash)
-  checkAll("Monoid[Map[String, Int]]", MonoidLawTests[Map[String, Int]].monoid)
-  checkAll("Monoid[Map[String, Int]]", SerializableTests.serializable(Monoid[Map[String, Int]]))
+  checkAll("Hash[SortedMap[Int, String]]" , HashLawTests[SortedMap[Int, String]].hash)
+  checkAll("Monoid[SortedMap[String, Int]]", MonoidLawTests[SortedMap[String, Int]].monoid)
+  checkAll("Monoid[SortedMap[String, Int]]", SerializableTests.serializable(Monoid[SortedMap[String, Int]]))
 }