The 1999-2000 I-Divisioona season was the 26th and final season of the I-Divisioona, the second level of Finnish ice hockey. The second-level Finnish league became the Mestis for the 2000-01 season. 12 teams participated in the league, and Kärpät Oulu, Vaasan Sport, and Diskos Jyväskylä qualified for the promotion/relegation round of the SM-liiga.