A spin glass (SG) phase was observed in the spin-density wave (SDW) alloys Cr1−xCox at high Co concentrations (x≥13%). After zero-field cooling, the temperature dependence of the magnetization M(T) of Cr0.87Co0.13 and Cr0.85Co0.15, measured in an applied field H=100 Oe with a SQUID magnetometer, exhibits a low T maximum, characteristic of a SG. Cooling in the measuring field, however, gives quite a different behavior. The field dependence of the magnetization M(H) is nonlinear, with a pronounced hysteresis. A strong time relaxation M(t) is also an indication of a SG phase. SG in Cr1−xCox is formed at high impurity concentrations, possibly due to clustering of the magnetic impurities.