- Astellas US Holding, Inc.
- Astellas US LLC
- Astellas Pharma US,Inc.
- Astellas Pharma Global Development, Inc.
- Astellas US Technologies, Inc.
- Astellas Pharma Technologies, Inc.
- Astellas Research Institutes of America LLC
- Astellas Venture Management LLC
- Astellas Pharma Canada, Inc.
- Astellas Farma Brasil Importacao e Distribuicao de Medicamentos Ltda.
- Agensys, Inc
- OSI Pharmaceuticals LLC
- Astellas B.V.
- Astellas Pharma Europe Ltd.
- Astellas Pharma Europe B.V.
- Astellas Ireland Co., Ltd.