Men in sub-Saharan Africa have low HIV testing rates. Social networks exert an important influence on men's HIV-related behavior. We examined associations between network factors and HIV testing among men in Dar es Salaam, Tanzania. Data are from the baseline assessment of an HIV prevention trial with 48 primarily male networks. Among 923 sexually active men, 52 % had ever tested for HIV. In a random effects logistic regression model, men in the network core were 1.50 times more likely (p < .05) to test than those in the periphery. Percentage of women in the network was associated with men's increased HIV testing (AOR 4.24, p < .05). Perception of network HIV stigma was negatively associated with HIV testing (AOR 0.92, p < .01). Thinking at least one close friend tested for HIV was associated with increased testing (AOR 2.66, p < .001). Social network interventions are a promising approach for scaling up men's HIV testing.