The 1990-91 Division 1 season was the 27th of the competition of the first-tier football in Senegal. The tournament was organized by the Senegalese Football Federation. ASC Port Autonome won the second title and participated in the 1992 African Cup of Champions Clubs the following year. ASC Diaraf participated in the 1992 CAF Cup, ASEC Ndiambour in the 1992 CAF Winners' Cup and ASC Jeanne d'Arc in the 1992 West African Cup.
SEIB Diourbel was the defending team of the title. A total of 16 clubs participated in the competition. The season featured 450 matches and scored 429 goals. No new clubs came from the second division (Division 2).
Participating clubs
US Gorée
SEIB Diourbel
ASC Port Autonome
Dialdiop SC
AS Douanes
ASC Jeanne d'Arc
Casa Sports
US Ouakam
SIDEC Dakar
ASC Diaraf
Stade de Mbour
US Rail
ASC Linguère
ETICS Mboro
ASC Mbosse Kaolack
ASEC Ndiambour
Overview
The league was contested by 14 teams with ASC Port Autonome winning the championship.