| 1199SEIU in Williamsville, NY | AMERIGROUP in Williamsville, NY |
| APS Healthcare in Williamsville, NY | Aetna in Williamsville, NY |
| Alliance in Williamsville, NY | AmeriHealth in Williamsville, NY |
| American Behavioral in Williamsville, NY | Beech Street in Williamsville, NY |
| Behavioral Health Systems in Williamsville, NY | BlueCross and/or BlueShield in Williamsville, NY |
| CCN in Williamsville, NY | CHIPA/College Health in Williamsville, NY |
| Cascade Health in Williamsville, NY | Ceridian in Williamsville, NY |
| ChoiceCare in Williamsville, NY | Cigna in Williamsville, NY |
| ComPsych in Williamsville, NY | Corphealth in Williamsville, NY |
| Coventry in Williamsville, NY | First Choice Health in Williamsville, NY |
| First Health in Williamsville, NY | GHI/Group Health Incorporated in Williamsville, NY |
| Great-West in Williamsville, NY | Guardian in Williamsville, NY |
| HFN in Williamsville, NY | HIP/Health Plan of New York in Williamsville, NY |
| Harvard Pilgrim Health Care in Williamsville, NY | Health Net in Williamsville, NY |
| Holman Group in Williamsville, NY | Horizon Healthcare in Williamsville, NY |
| Humana in Williamsville, NY | Integrated Health Plan in Williamsville, NY |
| Interplan in Williamsville, NY | Kaiser in Williamsville, NY |
| LifeWise in Williamsville, NY | MAMSI in Williamsville, NY |
| MHN/Managed Health Network in Williamsville, NY | Magellan Behavioral Health in Williamsville, NY |
| MagnaCare in Williamsville, NY | Medica in Williamsville, NY |
| Medicaid in Williamsville, NY | Medical Mutual in Williamsville, NY |
| Medicare in Williamsville, NY | Multiplan in Williamsville, NY |
| NCPPO in Williamsville, NY | ODS in Williamsville, NY |
| Oxford in Williamsville, NY | PHCS/Private Health Care Systems in Williamsville, NY |
| PPOM in Williamsville, NY | PacifiCare in Williamsville, NY |
| PacificSource in Williamsville, NY | PreferredOne in Williamsville, NY |
| Providence in Williamsville, NY | Sloans Lake in Williamsville, NY |
| TRICARE in Williamsville, NY | TriWest0127 in Williamsville, NY |
| Tufts in Williamsville, NY | UniCare in Williamsville, NY |
| Uniform in Williamsville, NY | United in Williamsville, NY |
| VMC in Williamsville, NY | ValueOptions in Williamsville, NY |
| WellPoint in Williamsville, NY |