| 601 | ROX | Richfield Oil Co. of California | 7/1930-7/1935 | | NAKINA |
| 602 | ROX | Richfield Oil Corporation | 4/38-7/65; eliminated 7/66 | | NRHS |
| 603 | ROX | Atlantic Richfield Co. | added 7/66; 10/66-4/70; eliminated 1/72 | | NRHS |
| 604 | ROX | ATLANTIC RICHFIELD CO. [RICHFIELD OIL CORP.] | | | PWRC |
| 605 | ROXB | ROXBURY TRUCKING CO INC | | | SCAC3 |
| 606 | ROXC | RIO EXPRESS (MX-374938) | | | SCAC4 |
| 607 | ROXE | ROAD ONE (1) EXPRESS INC | | | SCAC4 |
| 608 | ROXM | ROXMAN TRUCKING | | | SCAC4 |
| 609 | ROXN | R & O TRANSFER | | | SCAC4 |
| 610 | ROXS | ROCKET EXPRESS INTERNATIONAL | | | SCAC3 |
| 611 | ROXS | ROCKET EXPRESS COURIER | | | SCAC4 |
| 612 | ROXT | ROLLIN-ON EXPRESS TRUCKING INC | | | SCAC3 |
| 613 | ROXT | ROMEX TRANSPORT INC | | | SCAC4 |
| 614 | ROXU | EMCO MARINE LTD / CONTAINERS DPT. | | IL | BIC |
| 615 | ROXU | EMCO MARINE LTD / CONTAINERS DPT | | | SCAC4 |
| 616 | ROXX | Rocky Mountain Recycling, Inc. | added 4/2007; eliminated 7/2007; added 1/2009 | | NAKINA |
| 617 | ROXX | ROCKY MOUNTIAN RECYCLING, INC. | | | PWRC |
| 618 | ROXX | ROCKY MOUNTAIN RECYCLING INC | | | SCAC4 |
| 619 | ROY | Royal Aviation, Inc. | IATA: QN, IATA Prefix: 498, Merged in Canada 3000 | CDN | AVCODES |
| 620 | ROY | Pacific Royale Airways, PT. | Callsign: Paxroy, ICAO designator changed to PRQ. ICAO callsign changed to Skyrider | RI | AVCODES |
| 621 | ROY | Roy Ritter Sky Dive | Callsign: Sky Dive, | IL | AVCODES |
| 622 | ROY | Conifair Aviation | | | ICAO1 |
| 623 | ROY | STE ROY | | FR | VKM |
| 624 | ROYC | ROYAL TRAFFIC | | | SCAC4 |
| 625 | ROYD | ROYAL CREST DISTRIBUTORS INC | | | SCAC3 |
| 626 | ROYE | ROYAL EXPRESS INC | | | SCAC4 |
| 627 | ROYF | ROYAL LOGISTICS INC | | | SCAC4 |
| 628 | ROYG | ROYALE CARTAGE INC | | | SCAC3 |
| 629 | ROYI | ROYS TRANSFER INC | | | SCAC3 |
| 630 | ROYI | ROYS TRANSFER INC | | | SCAC4 |
| 631 | ROYJ | ROYAL ELECTRIC SUPPLY COMPANY | | | SCAC4 |
| 632 | ROYK | ROY, MARK | | | SCAC4 |
| 633 | ROYL | ROYAL TRANSPORTATION LIMITED | | | SCAC3 |
| 634 | ROYL | ROYAL TRANSPORTATION LIMITED | | | SCAC4 |
| 635 | ROYM | ROYAL MARITIME CORPORATION | | | SCAC4 |
| 636 | ROYN | ROYAL MESSENGER SERVICE | | | SCAC3 |
| 637 | ROYN | ROY, MARTIN TRANSPORT | | | SCAC4 |
| 638 | ROYP | ROYAL TRANSPORT INC | | | SCAC3 |
| 639 | ROYP | ROYAL TRANSPORT INC | | | SCAC4 |
| 640 | ROYQ | ROYAL TRUCKING | | | SCAC4 |
| 641 | ROYR | ROY BROS, INC | | | SCAC3 |
| 642 | ROYR | ROY BROS INC | | | SCAC4 |
| 643 | ROYS | ROYS TRANSFER SERVICE | | | SCAC3 |
| 644 | ROYT | ROYSTER TRUCKING INC | | | SCAC3 |
| 645 | ROYT | ROYSTER TRUCKING INC | | | SCAC4 |
| 646 | ROYU | ROYAL NETHERLANDS | | | PWRC |
| 647 | ROYU | Royal Netherlands | | | RSRV |
| 648 | ROYU | ROYAL NETHERLANDS STEAMSHIP CO | | | SCAC3 |
| 649 | ROYX | Chartrand's Tank Car Service, Inc. | eliminated 1/1991 | | NAKINA |
| 650 | ROYX | TCL, Inc. | added 7/1973; 1/1975-1/1980; eliminated 10/1988 | | NAKINA |
| 651 | ROYX | Chartrand's Tank Car Service, Inc. | eliminated 1/91 | | NRHS |
| 652 | ROYX | TCL, Inc. | added 7/73; 1/75-1/80; eliminated 10/88 | | NRHS |
| 653 | ROYX | *TCL INC. | | | PWRC |
| 654 | ROYX | *CHARTRAND'S TANK CAR SERVICE, INC. | | | PWRC |
| 655 | ROYX | TCL | | | RSRV |
| 656 | ROYY | ROYAL TRANSPORT LTD | | | SCAC4 |
| 657 | ROZB | ROZELLE, BENJAMIN F | | | SCAC3 |
| 658 | ROZI | ROZIERS OIL COMPANY | | | SCAC4 |
| 659 | ROZK | ROZAK TRUCKING | | | SCAC3 |
| 660 | ROZL | RIO AZUL COMPANIA ARMADORA S A | | | SCAC3 |
| 661 | ROZL | RODRIGUEZ ZAVALA, JOSE | | | SCAC4 |
| 662 | ROZN | ROZON, MICHEL TRANSPORT | | | SCAC4 |
| 663 | ROZO | ROYAL MOTOR LINES INC | | | SCAC3 |
| 664 | ROZO | RODRIGUEZ ZAMBRANO, MACARENA DEL RO | | | SCAC4 |
