Young men who have sex with men (MSM) represent an increasing number of new HIV infections in many communities. Many individuals still hold beliefs that may lead to discrimination against HIV-positive individuals. HIV stigma is associated with negative health and psychosocial outcomes and may lead to greater challenges for this marginalized population. This study describes stigma experienced by HIV-positive young MSM, explores its relationship to psychosocial measures, and tests the hypothesis that stigma scores will be higher in those diagnosed less than 1 year ago versus more than 1 year. From August 2004 to September 2005 young MSM completed a questionnaire including demographic information and psychosocial measures. Descriptive and bivariate analyses of association were used to interpret data from the total stigma scale and four subscales: personalized stigma (PS), public attitudes (PA), negative self-image (NSI), and disclosure concerns (DC). Index scores were calculated by standardizing each subscale for direct comparisons. The 42 participants were: mean 21.3 years; 45% black, 24% Hispanic, 26% white; 14% transgender; and 50% diagnosed HIV-positive less than 1 year. Participants reported HIV-related stigma across all domains with mean index subscale scores: PS 0.57, PA 0.61, NSI 0.63, DC 0.75 indicating that disclosure concerns were prevalent in comparison to other forms of HIV-related stigma. Stigma scores correlated with depression, social support, self-esteem, and romantic loneliness. Stigma scores did not differ for those diagnosed less than 1 year ago versus more than 1 year ago. Providers should address HIV-related stigma concerns, particularly disclosure, throughout the trajectory of the illness when caring for HIV-positive young MSM as a factor affecting health outcomes and psychosocial functioning.