diff --git a/thirdeye-core/src/main/java/ai/startree/thirdeye/datasource/DataSourceOnboarder.java b/thirdeye-core/src/main/java/ai/startree/thirdeye/datasource/DataSourceOnboarder.java
index bd995450c0..642f965037 100644
--- a/thirdeye-core/src/main/java/ai/startree/thirdeye/datasource/DataSourceOnboarder.java
+++ b/thirdeye-core/src/main/java/ai/startree/thirdeye/datasource/DataSourceOnboarder.java
@@ -129,6 +129,11 @@ private DatasetConfigDTO persist(final DatasetConfigDTO datasetConfigDTO,
     final List<MetricConfigDTO> metrics = datasetConfigDTO.getMetrics();
     datasetConfigDTO.setAuth(auth);
     datasetConfigDTO.setMetrics(null);
+    final DatasetConfigDTO existingDatasetConfig = datasetConfigManager.findUniqueByNameAndNamespace(
+        datasetConfigDTO.getDataset(), datasetConfigDTO.namespace());
+    checkState(existingDatasetConfig == null,
+        "Dataset with name %s already exists in namespace %s",
+        datasetConfigDTO.getDataset(), datasetConfigDTO.namespace());
     final Long datasetId = datasetConfigManager.save(datasetConfigDTO);
     checkState(datasetId != null, "Failed creating dataset %s", datasetConfigDTO.getDataset());