| Colourcoding Media | Ontario |
| Coltech Electronics Ltd | Ontario |
| Colton Communications | Alberta |
| Columbia Networks | |
| Columbia Wireless | British Columbia |
| Columbus Networks | British Columbia |
| Columna Soft, Inc. | Ontario |
| Com9 Informatique | Quebec |
| CoMac Technologies, Inc. | Ontario |
| Combat Computers, Inc. | Prince Edward Island |
| Combustible | Quebec |
| Comcanada Communications, Inc. | British Columbia |
| Comco | Saskatchewan |
| Comcorp Communications, Inc.. | Ontario |
| Comdic | |
| Comdic Ltée | Quebec |
| Comeleon | |
| Comet Telecom | Ontario |
| ComExel | |
| Comfable, Inc. | Ontario |
| Comfort Software Group | British Columbia |
| Comgate Engineering Ltd | Ontario |
| Coming IT Services | Ontario |
| Comité sectoriel de main-d'oeuvre en aérospatiale au Québec | Quebec |
| Comlab Télécommunications, Inc. | Quebec |
| Comm100 Network Corporation | British Columbia |
| Comma Imagination | |
| Command Base | |
| Commandare Technologies | Quebec |
| CommandIR Control Technologies | Ontario |
| Commbits | Ontario |
| Commerce Dynamics | |
| Commerce Pros | |
| Commerce7 | |
| Commercial Electronics Ltd | British Columbia |
| Commercial Laser Technologies, Inc. | Ontario |
| Commerx | Alberta |
| Commerx Computer Systems, Inc. | Ontario |
| Commission d'accès à l'information du Québec | Quebec |
| Commission de développement économique des Premières Nations du Québec et du Labrador | |
| Commodore Computer Sitelist | Ontario |
| Commodore.ca | Ontario |
| Common Sense Computer Consulting, Inc. | Alberta |
| Common University Data Ontario | Ontario |
| CommonGoals Software | Ontario |
| CommonOffice | |
| commonsku | Ontario |
| Commonwealth College | |
| Commpath | Ontario |
| Commport Communications International, Inc. | Ontario |