Exhibit 21.1

Subsidiaries of Rhythm Pharmaceuticals, Inc.

Entity		Jurisdiction of Organization or Incorporation
Rhythm Pharmaceuticals Limited		Ireland
Rhythm Securities Corp.		Massachusetts
Rhythm Pharmaceuticals Netherlands, B.V.		The Netherlands
Rhythm Pharmaceuticals UK Limited Rhythm Pharmaceuticals France SAS Rhythm Pharmaceuticals Italy S.r.L. Rhythm Pharmaceuticals Canada Inc.		United Kingdom France Italy Canada
Rhythm Pharmaceuticals Germany GmbH		Germany
Xinvento, B.V.	The Netherlands
Rhythm Pharmaceuticals Spain S.L.		Spain