Redundant color information improved performance for both sexes on the Shepard Mental Rotations Task (MRT; Shepard & Metzler, 1971). Absolute score gains for women were larger than those for men; therefore, relative improvement was greater. Substantial practice effects, also favoring women, were apparent in both studies. Study 1 showed that redundant color improved performance by 0.25 SD. Study 2 demonstrated that redundant black-and-white pattern information did not have any effect; a second visuospatial channel, redundant color, was a critical factor in improving scores of men and women on difficult mental rotations tasks.