| 1230 Électroniques | Lachine | Computer Repair & Cleaning |
| 123inkcartridges.ca | Lachine | Camera & Photo Equipment Stores |
| 9132-1000 Québec Inc | Lachine | Business & Trade Organizations |
| 9141-2148 Québec Inc | Westmount | Cleaning Services, Cleaning Service |
| 9334-4349 Quebec Inc | Lachine | Pizza & Pizzerias |
| A Asselin & Fils Inc | Lachine | Plumbing |
| A Pex Discount Inc | Lachine | Bedding & Linens |
| A S T Inc | Montréal | Business & Trade Organizations |
| A+Quick Socal Media Business | Montréal | Advertising Agencies |
| Aai Encanteurs Assoc Intl | Lachine | Auctions |
Publicité (Desktop) Publicité (Mobile) |
| ABP Consultants en personnel | Westmount | Tout Entreprises et services |
| Abu-Lasia/ Matamin | Lachine | Baked Goods Wholesalers |
| ABZ Assurances-Insurance | Westmount | Car Insurance |
| ACA | Westmount | Collection Agencies |
| Académie Ballet Flamenco Lina Moros | Westmount | Tout Enseignement et savoir |
| Accessoires Rose Blanche | Lachine | Bakery Equipment, Bakery Supplies |
| Accord Expositions | Lachine | Tout Entreprises et services |
| Acier Lachine Inc | Lachine | Aluminum |
| Acier Wirth Steel | Westmount | Aluminum |
| Action Graphix Longueil | Longueuil | Business Centres |
Publicité (Desktop) Publicité (Mobile) |
| Action Sport Physio | Westmount | Tout Entreprises et services, Physiotherapy |
| Active Business & Realty Inc | Mont-Royal | Business Brokers |
| Adelman, Adam | Westmount | Boutiques |
| Adelson Et Associés | Montréal | Business Insurance |
| ADI Global Distribution | Lachine | Tout Entreprises et services |
| ADM Canada | Lachine | Tout Entreprises et services |
| Advanced Business Analytics Inc. | Montréal | Physiotherapy |
| Advanceit Financial Corp | Westmount | Computer Networking |
| Aerotek | Montréal | Business Centres |
| Affiliated Sport Group | Lachine | Tout Entreprises et services |
Publicité (Desktop) Publicité (Mobile) |
| Agence Imapro Inc | Lachine | Business & Trade Organizations |
| Agences Roger Boutin Inc | Boucherville | Business Brokers |
| AIDA Distribution | Lachine | Beverage Distributors & Bottlers |
| Air Pro Transport 2009 | Lachine | Air Cargo Service |
| Air-Therm Inc | Westmount | Plumbing |
| Alain Lessard | Montréal | Business Lawyers |
| Alain Normandin Rénovation | Lachine | Home Improvement |
| Albert Seliger | Montréal | Business Insurance |
| ALCiE Integrated Business Solutions | Montréal | Tout Informatique et internet |
| Alexandre Germain | Longueuil | Business Lawyers |
Publicité (Desktop) Publicité (Mobile) |
| Aliments Morehouse Canada Inc | Lachine | Agri-food |
| Aliments T & N (Les) | Lachine | Agri-food |
| Allali Brault | Montréal | Business Lawyers |
| Alliance Web-Commerce | Montréal | Business & Trade Organizations |
| AlloFirm | Montréal | Business Brokers |
| Allstream | Lachine | Information Technologies (IT), Tout Entreprises et services, Tout Informatique et internet |
| Alongi | Lachine | Tout Commerces au détail, Tout Entreprises et services |
| Altea Furniture | Westmount | Antique Restoration, Refinishing & Repair |
| Always B Clean | Lachine | Home Improvement |
| AM1280 CFMB | Westmount | Tout Médias montréalais |
