Exhibit 21 WAM!NET Inc. Corporate Structure (all subsidiaries are 100% directly or indirectly owned by Wam!Net Inc.) WAM!NET Inc., a Minnesota corporation owns 100% of the following companies: WAM!NET International Inc., a Minnesota corporation FreeMail, Inc., a Minnesota corporation Medical Digital, Inc., a Minnesota corporation NetCo Communications of Canada, Inc., an Ontario corporation WAM!NET ROC (Belgium), a Belgium corporation WAM!NET Holdings (UK) Limited, a company incorporated under the laws of England and Wales which owns 100% of the following company: WAM!NET UK Limited, a company incorporated under the laws of England and Wales which owns 100% of the following companies: 4-Sight International Limited, a company incorporated under the laws of England and Wales 4-Sight Software Limited, a company incorporated under the laws of England and Wales 4-Sight, Inc., a Delaware corporation (US) WAM!NET (Deutscheland) gmbH, a German corporation WAM!NET (Netherlands) B.V., a company organized under the laws of the Netherlands