| Mobile Telephone Service | 283 |
| Modeling Agencies | 283 |
| Modeling Schools | 283 |
| Modular Homes | 283 |
| Moisture Control | 283 |
| Molasses | 284 |
| Mold & Mildew Services | 284 |
| Money Transfer Service | 285 |
| Monograms | 285 |
| Mortgages | 285 |
| Motel & Hotel Equipment & Supplies | 287 |
| Motels | 287 |
| Motion Picture Equipment & Supplies | 287 |
| Motor Homes-Renting & Leasing | 287 |
| Motorcycles & Motor Scooters- New & Used | 287 |
| Motorcycles & Motor Scooters- Supplies & Parts- | 287 |
| Whsle & Mfrs |
| Movers | 288 |
| Moving Equipment Rental | 289 |
| Moving Services-Labor & Materials | 289 |
| Moving Supplies | 289 |
| MRI Magnetic Resonance Imaging | 289 |
| Murals | 289 |
| Museums | 289 |
| Music Arrangers & Composers | 290 |
| Music Instruction-Instrumental | 290 |
| Musical Instruments-Dealers | 290 |
| Musical Instruments-Renting & Leasing | 290 |
| Musical Instruments-Repairing | 290 |
| Music-Background & Foreground | 290 |
| Musicians | 290 |
| Mutual Funds | 291 |
| N |
| Nail Salons | 291 |
| Name Plates | 291 |
| Naval Architects | 291 |
| Neckwear | 291 |
| Needlework & Needlework Materials | 291 |
| Negotiation Services | 291 |
| Nets & Nettings | 291 |
| Network Consultants | 291 |
| News Dealers | 291 |
| News Service | 292 |
| Newspapers | 292 |
| Nightclubs | 293 |
| Notaries-Public | 294 |
| Novelties | 294 |
| Nurseries-Plants, Trees, Etc | 294 |
| Nurses | 294 |
| Nurses’ Registries | 294 |
| Nursing Homes | 295 |
| Nuts-Edible | 295 |
| O |
| Occult Supplies | 295 |
| Occupational Therapists | 295 |
| Oceanographers | 295 |
| Office Buildings | 295 |