This study investigated sexual identity and behavior and their potential associations with PrEP use and attitudes in cisgender Black gay and bisexual men. A total of N = 173 (mean age 25.2) participants from the Neighborhoods and Networks (N2) Study in Chicago were included. Of these, 104 were gay-identified and reported sex with men only (GSMO), 26 were gay-identified and reported sex with men and women (GSMW), 8 were bisexual-identified and reported sex with men only (BSMO), and 35 were bisexual-identified and reported sex with men and women (BSMW). Reporting sex with men and women in the past 6 months, RR = 0.39, 95% CI [0.17, 0.89], identifying as bisexual, RR = 0.52, 95% CI [0.29, 0.92], and the combination of the two, RR = 0.24, 95% CI [0.07, 0.76] were significantly associated with lower rates of current oral PrEP use. Black bisexual-identifying men who reported sex with men and women were significantly more likely to have discontinued oral PrEP, RR = 2.50, 95% CI [1.14, 5.50], than Black gay-identified men who reported sex with men only. Participants who had not used oral PrEP before reported lower levels of interest in long-acting injectable PrEP than those who were currently using oral PrEP, RR = 0.56, 95% CI [0.40, 0.79]. No other significant differences were found. Overlooking the combination of sexual identity and behavior may mischaracterize PrEP rates and miss uniquely vulnerable subgroups. Black gay and bisexual men who had not used oral PrEP may be particularly disinterested in long-acting injectable PrEP.