diff --git a/Lib/mimetypes.py b/Lib/mimetypes.py
index f25872102b8c27..80d9a3f88d0f4e 100644
--- a/Lib/mimetypes.py
+++ b/Lib/mimetypes.py
@@ -514,6 +514,7 @@ def _default_mime_types():
         '.txt'    : 'text/plain',
         '.ustar'  : 'application/x-ustar',
         '.vcf'    : 'text/x-vcard',
+        '.wasm'   : 'application/wasm',
         '.wav'    : 'audio/x-wav',
         '.webm'   : 'video/webm',
         '.wiz'    : 'application/msword',
diff --git a/Misc/NEWS.d/next/Library/2018-09-26-14-09-34.bpo-34758.bRBfAi.rst b/Misc/NEWS.d/next/Library/2018-09-26-14-09-34.bpo-34758.bRBfAi.rst
new file mode 100644
index 00000000000000..82e38aa6e158bc
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-09-26-14-09-34.bpo-34758.bRBfAi.rst
@@ -0,0 +1,2 @@
+Add .wasm -> application/wasm to list of recognized file types and content
+type headers