This study examined the effects of playing by ear in selected keys on the abilities of musicians (N = 28) to play by ear and sight-read in those keys. Middle school band students in the experimental group learned melodies by ear in one familiar and two unfamiliar keys, and did no music reading in the new keys, while students in the contact-control group practiced technical exercises from notation. The experimental group improved significantly in playing by ear in the two new keys, but not in the familiar key, while the contact-control group did not improve in any of the keys. Both groups improved in sight-reading in all keys. Responding to an attitude survey, only students in the experimental group perceived any improvement in performance, specifically in the new keys. The results of the study suggest the potential benefits of playing by ear as preparation for sight-reading in new keys.