[en] The general results on the 1st intercomparison of ac loss measurements executed in 1988-1989 in the framework of VAMAS are presented. 15 laboratories from 5 countries participated in the program. 4 different NbTi sample wires, referred to as samples D, E, F and G, were used. For samples D and E hysteresis losses for the field application sequence of 1 → 0 → 1 T and coupling time constants estimated from the ac coupling losses were intercompared. The scatters in hysteresis data in terms of standard deviation was about 10% for both of samples D and E, which are rather smaller compared to those in coupling time constant data. Coil losses were measured on samples F and G as a function of ac transport current and intercompared. Results and possible reasons for the data scatters and discussed