This paper examined correlates of consistent condom use with a main partner among heterosexual male injection drug users (IDUs). Using data from a multi-site sample of young IDUs, we identified 1770 sexually active men of whom 24% (429/1770) reported an exclusive main female sex partner and 49% (862/1770) reported both main and casual female sex partners. Consistent condom use with a main partner was low among men with an exclusive main partner and those with multiple partners (12% and 17%, respectively). In multivariate analysis, consistent condom use with a main partner across partnership patterns was directly associated with anticipating a positive response to requests for condom use and by partner support of condom use; consistent condom use was inversely associated with a main partner's pregnancy desires. Among men with an exclusive main partner, consistent condom use was also inversely associated with needle sharing with a main partner. Among men with multiple partners, consistent condom use with a main partner was inversely associated with injecting with a used needle and intimate partner violence. The low prevalence of consistent condom use with main female partners among heterosexually active male IDUs indicates an increased risk for HIV transmission between men and their primary sex partners. Interventions for heterosexual males that are geared toward increasing condom use in primary relationships are warranted.