The accident brought to 26 the number of people killed in the past two days in road accidents involving members of the Senegalese Muslim Mouride brotherhood heading to the town of Touba for their annual pilgrimage.
"A head-on collision between a bus and a minibus... left 18 dead, 13 seriously wounded and three more with light wounds," a member of the fire brigade involved in the rescue effort said.
The wounded were taken to the larger town of Thies, west of the capital Dakar, for treatment.
The Magal pilgrimage commemorates the 1895 exile to Gabon of Cheikh Ahmadou Bamba, who founded the Mouride brotherhood in 1883.
The brotherhood remains very influential in Senegal, whose population is 95 per cent Muslim, and the Magal draws millions every year to Touba, the movement's spiritual capital.
Both President Macky Sall and his predecessor Abdoulaye Wade are members of the brotherhood. Sall, who was elected in March, recently made the Magal an official annual holiday.