A power transmission belt (10) having a body (12) with a length, an inside and an outside. Teeth (14) are spaced along the length of the body. The body is made of rubber in which at least one load carrying member (26) is embedded. The load carrying member extends lengthwise of the body. The rubber in the body is made up of: a) 3 to 7 parts by mass of short fiber blended relative to 100 parts by mass of a polymer that is a hydrogenated nitrile rubber having unsaturated carboxylic acid metal salt formed by mixing the hydrogenated nitrile rubber and the unsaturated carboxylic acid metal salt at a mass ratio of from 100:100 to 100:180; and b) no more than 10 parts by mass of a powdery inorganic filler blended relative to 100 parts by mass of the polymer.