A key opportunity to reduce HIV transmission lies with healthcare providers counseling HIV-infected patients about safer sex. We audio-recorded and transcribed clinical encounters between 45 healthcare providers and 417 of their HIV-infected patients at four outpatient sites in the United States. We used logistic regressions to evaluate associations between patient and provider characteristics, and the occurrence of discussion (any talk about sex) and counseling (advice about safer sex). Of the 417 encounters, discussion of sex occurred in 187 (45% of encounters, 95% CI: 40-50%). Counseling occurred for 49% (95% CI: 35-63%) of patients reporting unsafe sex. Discussion of sex was more likely with younger or less-educated patients and with less cultural difference between patient and provider, while counseling was associated with greater provider mindfulness and lower provider empathy. These findings suggest targets to improve communication regarding sexual risk reduction in HIV care.