Super League IV
JJB Sports Super League IV was the official name for the year 1999's Super League championship season, the 105th season of top-level professional rugby league football in Britain, and the fourth championship run by Super League. The start of Super League IV saw the emergence of a North East based Rugby League Club, Gateshead Thunder as well as newly promoted Wakefield Trinity Wildcats to expand the league to fourteen teams.
Rule changes
- The 40/20 rule was introduced to reward accurate kicking in general play. The rule, which had been used in Australia since 1997, gave the head and feed at the resulting scrum to a team that kicked the ball from behind their 40-metre line so that it bounced in the field of play before going into touch behind their opponent's 20 metre line.
Teams
| Team | Stadium | Capacity | City/Area | |
| Bradford Bulls | Odsal | 27,000 | Bradford, West Yorkshire | |
| Castleford Tigers | Wheldon Road | 11,750 | Castleford, West Yorkshire | |
| Halifax Blue Sox | Thrum Hall | 9,832 | Halifax, West Yorkshire | |
| Huddersfield Giants | Galpharm Stadium | 24,500 | Huddersfield, West Yorkshire | |
| Hull Sharks | The Boulevard | 10,500 | Hull, East Riding of Yorkshire | |
| Leeds Rhinos | Headingley | 21,500 | Leeds, West Yorkshire | |
| London Broncos | The Valley | 27,000 | Charlton, Greater London | |
| Salford Reds | The Willows | 11,363 | Salford, Greater Manchester | |
| Sheffield Eagles | Don Valley Stadium | 25,000 | Sheffield, South Yorkshire | |
| St. Helens | Knowsley Road | 17,500 | St Helens, Mersyside | |
| Warrington Wolves | Wilderspool | 9,200 | Warrington, Cheshire | |
| Wigan Warriors | Central Park | 18,000 | Wigan, Greater Manchester |