The problem of degradation of rubber in conveyor belts is very important because they incorporate a lot of rubber and have a high value. In the paper we have analyzed the situation of rubber conveyor belts reinforced with metal insertions because it was found that they can sometimes be obsolete pretty fast due to the degradation of the connection between the metal insertion and the rubber matrix. The theoretical study performed followed modeling the bond between the metal insert and the rubber matrix and obtained a relationship for calculating the rate of degradation n d of the connection between the metal insertion and the rubber matrix. The evolution in time of the degradation of the connection between the metal insertion and the rubber matrix has also been established, and this was carried out during 2.5years of use of a conveyor belt type ST 3150. To analyze the degradation of the rubber from the conveyor belt, rubber hardness was determined for seven distinct points on the belt thickness at intervals of 0.5years and was also determined at the same intervals of time the evolution of specific resistance of tearing of the metal insertion from the rubber matrix.