2009–10 National First Division, was the season from August 2009 until February 2010, of South Africa's second tier of professional football. By the end of the season, the Coastal stream champion Vasco da Gama met to play the overall championship final, against the Inland stream champion Black Leopards. Vasco da Gama won the final, and thereby got promoted to Premier Soccer League. The subsequent playoff stage, was contested by the losing finalist, two second ranked teams of the NFD streams, and the second lowest ranked team of PSL. Winner of the playoff stage, and thereby the second promotion to PSL, was the team Mpumalanga Black Aces.

The league is made up of 16 teams, split into 2 streams. Each team plays the other 7 teams in their stream 3 times, for a total of 21 games. Teams receive 3 points for a win, 1 for draw, and 0 for a loss. At the end of the season, the top ranked team from each stream play in a two-legged final, the winner of which is crowned National First Division Champion, and gains automatic promotion to the Premier Soccer League for the next season. The loser of the final, along with the teams which came second in their streams, and the 15th placed PSL team, go into the PSL promotion play-offs. The two teams finishing in last place in their streams are automatically relegated to the Vodacom League. They are replaced by the finalists of the Vodacom League championship game.