Tuberculosis is the commonest HIV-1-related disease and the most frequent cause of mortality in young women in endemic regions. Tuberculosis and HIV-1 are independent risk factors for maternal mortality and adverse perinatal outcomes, and in combination have a greater impact on these parameters than their individual effects. In referral health centres in southern Africa around one-sixth of all maternal deaths are due to tuberculosis/HIV-1 coinfection. One-third (37%) of HIV-1-infected mothers with tuberculosis are severely immunocompromised, with CD4 counts of fewer than 200 cells/microL compared with 14-19% in mothers recruited into major mother-to-child intervention trials in Europe. Babies born to mothers with tuberculosis/HIV-1 also have higher rates of prematurity, low birthweight, and intrauterine growth restriction. Transmission rates of HIV-1 from mother to infant are around 25-45% in resource-limited settings, while that for mother-to-child-transmission of tuberculosis is 15% within 3 weeks of birth. We highlight this emergent problem, and discuss the dilemmas associated with diagnosis and management of pregnant HIV-1-infected mothers with tuberculosis, and their newborn babies.