During design of the envelope of a noncircular belt pulley one should take into account several conditions resulting from kinematics and geometry of the uneven-running strand transmission. Design of proper values of pitches for a belt pulley, which enable good cooperation between the belt pulley and the belt, should be carefully done. In available Polish literature and catalogues offered by belt manufacturers, one can find only detailed dimensions of belts with a trapezoidal profile. Information on other profiles is insufficient for full description of geometrical features of belt pulley teeth as well as to design tools for machining belt pulleys. Manufacturers of belt pulleys and belts give only necessary data to submit a purchase order. The paper presents a digitization process (scanning) of geometry of the envelope of circular belt pulleys with non-standard profiles; this scanning has been done with the application of coordinate measuring machines. The obtained information on geometrical features of tooth profiles has been numerically analysed. As a result of this analysis, the mathematical description has been obtained. Finally, noncircular belt pulleys with different tooth profiles have been designed and manufactured.