The 1991 Mountain Bike World Championships (30/6 October) were held in the tourist area called "Il Ciocco", in Castelvecchio Pascoli, in the municipality of Barga, in Italy. They were the first edition to take place in Italy and, at the same time, the first in Europe, according to the principle of alternation between European and non-European countries which characterized the succession of host venues in the first years of the World Cup.
They competed in two disciplines, the cross country and downhill, in three categories for each discipline (junior, senior and veteran), for a total of twelve world titles awarded. In Durango, in fact, the junior women's titles were not awarded, either in Cross Country or in Downhill due to the lack of the minimum number of members.