Аннотация:We present the results of photometric and magnetic monitoring of a well-known long-period Ap star GY And. This research was inspired by the unusual "secular" variability of the B - V color index. Photometric monitoring was carried out with the 60-cm reflector of the Crimean Laboratory of the Moscow State University, where 420 brightness estimates were obtained during 2011-2014 with the Johnson system broadband U, B, and V filters. Magnetic monitoring was carried out at the 1-m telescope of the Special Astrophysical Observatory. The duration of photometric observations is about 54 years, and the duration of magnetic monitoring is 64 years. As a result, we have refined the period and the parameters of variability of the magnetic field, and the photometric behavior. We demonstrate that the peculiar "secular" color variability is explained by the off-duty factor of the observations.