We examined the relationship between interval identification skill and error detection skill in preservice teachers, accounting for timbral differences by including piano and vocal stimuli. The interval identification test was comprised of 33 items spanning from C2 to B5. Fifteen error detection items were monophonic melodies, two measures long, in 4/4 meter, and included one pitch error. Music education majors (N = 50) completed both tests in vocal and piano timbres during one individual study session. Interval identification performance was significantly correlated with error detection performance, r = 0.75. Additionally, interval identification score was a significant predictor for error detection when also accounting for variance from numbers of semesters of enrollment and theory/aural skills courses. Response times for correct responses of interval identification were faster than for incorrect responses. We found no main effects or interactions between primary performance area and timbre of test item. The results suggest interval identification skill generally can be used to predict error detection, reinforcing the importance of developing interval identification as a basic musical skill.