diff --git a/exporters/stats/prometheus/src/main/java/io/opencensus/exporter/stats/prometheus/PrometheusExportUtils.java b/exporters/stats/prometheus/src/main/java/io/opencensus/exporter/stats/prometheus/PrometheusExportUtils.java
index b4588a50..d7cf2f74 100644
--- a/exporters/stats/prometheus/src/main/java/io/opencensus/exporter/stats/prometheus/PrometheusExportUtils.java
+++ b/exporters/stats/prometheus/src/main/java/io/opencensus/exporter/stats/prometheus/PrometheusExportUtils.java
@@ -140,7 +140,7 @@ final class PrometheusExportUtils {
     } else if (type == MetricDescriptor.Type.SUMMARY) {
       return Type.SUMMARY;
     }
-    return Type.UNTYPED;
+    return Type.UNKNOWN;
   }
 
   // Converts a point value in Metric to a list of Prometheus Samples.