Consort intrusion behavior has been proposed to largely function as a means of preventing or suppressing the reproductive activity of subordinate males. In the Japanese macaques of Arashiyama B troop this behavior was found to be ineffective in influencing female mate choice and affecting differential reproduction. Mainly directed towards the female of the pair intrusion resembled sexual solicitation and appeared to be an extension of consort behavior. Although the intruder male was almost always dominant over the other male, intrusion failed to provide priority of access to the estrous female as she most frequently chose to remain with her current partner. Copulations which were intruded upon were as likely to end in ejaculation as those which were undisturbed. Only a small proportion of intruder male-female pairs mated. Pairs that did mate were likely to have been in consort before or during the period in which intrusion occurred. No significant correlation was found between male rank order and number of possible females impregnated. Individual young, middle to lower ranking males were estimated to have been reproductively the most successful.