Building upon previous exploratory qualitative research (Kidd S.A. (2003) "Child Adol. Social Work J." 20(4):235-261), this paper examines the mental health implications of social stigma as it is experienced by homeless youth. Surveys conducted with 208 youths on the streets and in agencies in New York City and Toronto revealed significant associations between perceived stigma due to homeless status and sexual orientation, panhandling and sex trade involvement, and amount of time homeless. Higher perceived stigma was also related to low self esteem, loneliness, feeling trapped, and suicidal ideation, with guilt/self-blame due to homeless status having the strongest impact on mental health variables.