OBJECTIVE: To examine HIV risk behavior and HIV infection among new injectors in Tallinn, Estonia. Design and methods Data from two cross-sectional surveys of injecting drug users (IDUs) recruited from a syringe exchange program (N = 162, Study 1) or using respondent driven sampling (N = 350, Study 2). Behavioral surveys were administered; serum samples were collected for HIV testing. Subjects were categorized into new injectors (injecting < or = 3 years) and long-term injectors (injecting > 3 years). RESULTS: Twenty-eight of 161 (17%, Study 1) and 73/350 (21%, Study 2) of the study subjects were new injectors. HIV infection was substantial among the newer injectors: HIV prevalence was 50% (Study 1) and 34% (Study 2), and estimated HIV incidence 31/100 PY and 21/100 PY, respectively. In Study 2, new injectors were more likely to be female and ethnic Estonian and less likely to be injecting daily compared with long-term injectors. No significant difference was found among two groups on sharing injecting equipment or reported number of sexual partners. CONCLUSIONS: A continuing HIV epidemic among new injectors is of critical public health concern. Interventions to prevent initiation into injecting drug use and scaling up HIV prevention programs for IDUs in Estonia are of utmost importance.