Background In Peru, partner notification (PN) outcomes are correlated with its perceived importance. Data assessing perceptions of PN and its correlates among MSM/TW patient populations can help inform prevention interventions.

Methods MSM/TW in Lima diagnosed with HIV and/or STI within the last month were surveyed about their beliefs concerning both partner notification and practises among their peers. All analyses were stratified by partner type.

Results We recruited 390 MSM/TW (Ages: 18–60, Median: 28.5, IQR: 24–36) who identified as homosexual (63.0%), bisexual (16.0%), heterosexual (6.8%), and TW (14.2%). Overall, 93.3% and 73.3% of respondents considered it “Very” or “Somewhat Important” to notify stable and casual partners, respectively. 73.5% of respondents believed that “Few” or “None” of their peers would notify their stable partners, while 84.7% believed the same for casual partners.

There was no association between perceived importance of notifying stable partners and beliefs about peer notification of stable partners. Among subjects who reported that “Few” or “None” of their peers would notify their casual partners, 31.7% (52/164) of gays and 57.9% (22/38) of TW did not consider it important to notify casual partners while 90.9% (30/33) of gays and all (5/5) TW who reported “Most” or “All” peers would notify casual partners were likely to do the same themselves (all p < 0.05). Low perceived importance of notification for any partner type was associated with identification as TW, low educational level, and “pasivo” sexual role (all p < 0.05) with consistently lower importance placed on notifying casual compared with stable partners.

Conclusions Perceptions about PN vary by partner type with casual partner notification considered least important. Perceived peer notification practises may reflect individual beliefs or social norms of notification behaviour, especially among TW and gay-identified MSM. Understanding individual-level, partner-level, factors and societal contexts that influence these perceptions will better inform interventions to promote PN.