BACKGROUND: After decades of improved tuberculosis (TB) control in Russia, notification rates started to rise in 1992. Russia also faces a fast growing human immunodeficiency virus (HIV) epidemic. OBJECTIVE: To document the extent and characteristics of HIV co-infection in TB patients in St Petersburg, Russia. DESIGN: A prospective cross-sectional study of HIV co-infected culture-positive TB cases. Between 15 June 2002 and 31 March 2003, TB cases at the St Petersburg City TB hospitals and dispensaries were screened for HIV infection. At the HIV Prevention and Treatment Center, HIV-infected individuals were offered TB screening. RESULTS: Forty-nine HIV-infected culture-positive TB cases were identified, mainly at TB hospitals and dispensaries. Most were new pulmonary TB cases. The majority were young (69% ≤30 years of age), male (84%), unemployed (94%) individuals with a history of injection drug use (IDU) (92%), and, in 35% of cases a history of incarceration. Active case finding was high among contacts of cases (9%), but was not successful in HIV-infected IDUs. CONCLUSION: Although the HIV seroprevalence rate is rising among TB patients, HIV does not yet appear to be driving the St Petersburg TB epidemic. Aggressive collaborative TB-HIV control efforts may still avert adverse effects of HIV on the TB epidemic.