| Radio Station & Broadcasting Companies | 345 |
| Radioactivity Instruments, Supplies & Service | 346 |
| Radios-Citizens Band | 346 |
| Radiotelephone Communications- Common | 346 |
| Carrier |
| Railroad Contractors | 346 |
| Railroad Equipment & Supplies | 346 |
| Railroad Stations | 346 |
| Railroads | 346 |
| Railroads-Ticket Agencies | 346 |
| Rainwear | 346 |
| Range Hoods & Canopies | 346 |
| Ranges & Ovens-Service & Repair | 346 |
| Reading Improvement Instruction | 346 |
| Real Estate | 346 |
| Real Estate Appraisers | 347 |
| Real Estate Consultants | 348 |
| Real Estate Developers | 348 |
| Real Estate Inspection Service | 348 |
| Real Estate Loans | 348 |
| Real Estate Management | 348 |
| Real Estate Rental Service | 348 |
| Real Estate-Brokers | 348 |
| Real Estate-Commercial & Industrial | 348 |
| Record Companies | 348 |
| Recording Service-Sound & Video | 348 |
| Records Storage | 348 |
| Records, Tapes & Compact Discs | 349 |
| Recreation Centers | 349 |
| Recreational Vehicles-Dealers | 349 |
| Recreational Vehicles-Equipment, Parts & | 349 |
| Supplies |
| Recreational Vehicles-Repairing & Service | 349 |
| Recreational Vehicles-Storage | 349 |
| Recruiting-U.S. Armed Forces | 349 |
| Recycling Centers | 350 |
| Refreshment Stands | 350 |
| Refrigeration Equipment-Commercial & Industrial | 350 |
| -Sales & Service |
| Refrigeration Equipment-Supplies & Parts | 350 |
| Refrigeration-Industrial | 350 |
| Refrigerators & Freezers-Dealers | 350 |
| Refrigerators & Freezers-Service & Repair | 350 |
| Rehabilitation Services | 350 |
| Religious Goods | 351 |
| Religious Organizations | 351 |
| Rental Service Stores & Yards | 352 |
| Rental Vacancy Listing Service | 354 |
| Reptiles | 354 |
| Research & Development Centers | 354 |
| Research Service | 354 |
| Resorts | 354 |
| Respiratory Therapy | 354 |
| Rest Homes | 354 |
| Restaurant Equipment & Supplies | 354 |
| Restaurant Equipment-Repairing & Servicing | 354 |
| Restaurants | 356 |
| Restaurants-American | 372 |
| Restaurants-Bar & Grill | 372 |
| Restaurants-Breakfast | 372 |
| Restaurants-Buffet | 372 |
| Restaurants-Cafeterias | 372 |
| Restaurants-Cajun | 372 |
| Restaurants-Catfish | 372 |
| Restaurants-Chinese | 373 |
| Restaurants-Delivery & Carry Out | 373 |
| Restaurants-Italian | 373 |
| Restaurants-Japanese | 373 |
| Restaurants-Mexican | 373 |