Exhibit 21

SUBSIDIARIES OF RIOT BLOCKCHAIN, INC.

The following is a list of subsidiaries of the registrant, Riot Blockchain, Inc., a Nevada corporation (Nasdaq: RIOT), omitting subsidiaries which, considered in the aggregate as a single subsidiary, would not constitute a significant subsidiary of the registrant as of December 31, 2021:

We also have additional operating and holding company subsidiaries that, if considered in the aggregate as a single subsidiary, do not constitute a significant subsidiary.

All of the above listed subsidiaries have been consolidated in our consolidated financial statements.