Mackintosh and Bennett's [Mackintosh, N. J. and Bennett, E. S, (2005). ''What do Raven's Matrices measure? An analysis in terms of sex differences.'' Intelligence 33: 663-674.] study shows that males outperform females in some APM items but not in others, implicating that these items are measuring discriminable mental processes. The present comment was motivated by the fact that the sample size considered by these authors was small, thus raising the possibility of a lack of reliability. To replicate their findings, data from the Abad et al.'s [Abad, F. J., Colom, R., Rebollo, I., & Escorial, S. (2004). Sex differential item functioning in the Raven's Advanced Progressive Matrices: Evidence for bias. "Personality and Individual Differences," 36(6): 1459-1470.] study were re-analyzed, but following the same criteria employed by Mackintosh and Bennett. The results are not consistent with those reported in their study, indicating that average sex differences remain fairly constant across the same groups of APM items considered by them.