Let C be a class of ideals of the ring of algebraic numbers of an imaginary quadratic field. Let l and q be relatively prime integers, \(1 \leqslant q \leqslant \log ^{A_1 } x\), and A1 τ; 1. An asymptotic formula for the number π1(x, q, l, C) of prime ideals belonging to the class C whose norms do not exceed x and lie in an arithmetic progression is obtained in this paper. Bibliography: 6 titles.