Symptoms of sexually transmitted infections (STIs), whether they are presented for treatment or diagnosis, and how they are received by the clinician where they are presented, may be concomitants of stigma associated with homosexuality in homophobic climates. We analyzed respondent-driven sampling data from a study on 200 young men who have sex with men (MSM) in Dar es Salaam, Tanzania to examine sample prevalence, treatment and clinician response to 10 symptoms potentially associated with STIs. Survey measures included 10 self-reported STI symptoms, further specified according to location (genital, anal, oral), further specified according to place of diagnosis, place of, treatment whether there was pharmacy treatment or self-medication, healthcare worker (HCW) inquiries about source of infection and whether the HCW was polite. Most common symptoms reported were genital pain, burning urination, genital itching/burning, penile discharge, and groin swelling. Anal symptoms had the lowest proportion of treatment at public clinics and among the highest proportion of pharmacy treatment; anal sores had the highest proportion of self-medication. HCWs were reported as not being polite in response to 71–90% of the symptoms, (median = 82%). The findings suggest that stigma and negative HCW response are barriers to public clinic treatment for MSM in Tanzania and that these may have implications for both STI treatment and the HIV cascade.