CMI
- 901
- C-Media
- Cambridge–MIT Institute
- Canis Minor
- Carmelites of Mary Immaculate
- Case mix index
- Cell-mediated immunity
- Center for Medicare and Medicaid Innovation
- Certified Master Inspector
- Chartered Management Institute
- Chennai Mathematical Institute
- Chiang Mai Initiative
- Chicago Musical Instruments
- Chimei Innolux Corporation
- Chinese Maritime Institute
- Cimahi railway station
- Citibank
- Clay Mathematics Institute
- Coded mark inversion
- College of the Marshall Islands
- Comité Maritime International
- Committee for a Marxist International
- Computer Memories Inc.
- Content Management Interface
- Continental Micronesia
- Creation Ministries International
- Credit Managers' Index
- Crisis Management Initiative
- Culture and Media Institute
- Cummins
- Fairlight CMI
- Mental Illness
- The Curse of Monkey Island
- University of Illinois Willard Airport