diff --git a/HISTORY.md b/HISTORY.md
index cd8370b92..6fdd9c25a 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -16,6 +16,7 @@
 * Add NewFileChecksumGenCrc32cFactory to the file checksum public API, such that the builtin Crc32c based file checksum generator factory can be used by applications.
 * Add IsDirectory to Env and FS to indicate if a path is a directory.
 * Flush(..., column_family) may return Status::ColumnFamilyDropped() instead of Status::InvalidArgument() if column_family is dropped while processing the flush request.
+* BlobDB now explicitly disallows using the default column family's storage directories as blob directory.
 
 ### New Features
 * Added support for pipelined & parallel compression optimization for `BlockBasedTableBuilder`. This optimization makes block building, block compression and block appending a pipeline, and uses multiple threads to accelerate block compression. Users can set `CompressionOptions::parallel_threads` greater than 1 to enable compression parallelism. This feature is experimental for now.
diff --git a/utilities/blob_db/blob_db.h b/utilities/blob_db/blob_db.h
index 72a580433..47a679c2d 100644
--- a/utilities/blob_db/blob_db.h
+++ b/utilities/blob_db/blob_db.h
@@ -25,8 +25,9 @@ namespace blob_db {
 // users to use blob DB.
 
 struct BlobDBOptions {
-  // name of the directory under main db, where blobs will be stored.
-  // default is "blob_dir"
+  // Name of the directory under the base DB where blobs will be stored. Using
+  // a directory where the base DB stores its SST files is not supported.
+  // Default is "blob_dir"
   std::string blob_dir = "blob_dir";
 
   // whether the blob_dir path is relative or absolute.
diff --git a/utilities/blob_db/blob_db_impl.cc b/utilities/blob_db/blob_db_impl.cc
index bf3ad6426..824a7c689 100644
--- a/utilities/blob_db/blob_db_impl.cc
+++ b/utilities/blob_db/blob_db_impl.cc
@@ -211,6 +211,34 @@ Status BlobDBImpl::Open(std::vector<ColumnFamilyHandle*>* handles) {
   }
   db_impl_ = static_cast_with_check<DBImpl>(db_->GetRootDB());
 
+  // Sanitize the blob_dir provided. Using a directory where the
+  // base DB stores its files for the default CF is not supported.
+  const ColumnFamilyData* const cfd =
+      static_cast<ColumnFamilyHandleImpl*>(DefaultColumnFamily())->cfd();
+  assert(cfd);
+
+  const ImmutableCFOptions* const ioptions = cfd->ioptions();
+  assert(ioptions);
+
+  assert(env_);
+
+  for (const auto& cf_path : ioptions->cf_paths) {
+    bool blob_dir_same_as_cf_dir = false;
+    s = env_->AreFilesSame(blob_dir_, cf_path.path, &blob_dir_same_as_cf_dir);
+    if (!s.ok()) {
+      ROCKS_LOG_ERROR(db_options_.info_log,
+                      "Error while sanitizing blob_dir %s, status: %s",
+                      blob_dir_.c_str(), s.ToString().c_str());
+      return s;
+    }
+
+    if (blob_dir_same_as_cf_dir) {
+      return Status::NotSupported(
+          "Using the base DB's storage directories for BlobDB files is not "
+          "supported.");
+    }
+  }
+
   // Initialize SST file <-> oldest blob file mapping if garbage collection
   // is enabled.
   if (bdb_options_.enable_garbage_collection) {