Background: Despite public perception to the contrary, pregnancy does not offer a protective effect for suicide ideation. In low and middle income countries (LMIC) multiple concurrent risk factors including unplanned pregnancies, testing for HIV, intimate partner violence and depression may increase suicide risk among pregnant women. We examine suicide ideation among women attending routine antenatal care in rural South Africa. Method: A consecutive series of 109 women in the second half of pregnancy were enrolled in a cross-sectional study at a large primary health care facility in a rural area of KwaZulu-Natal with high HIV prevalence. Using a mixed-methods approach, women were assessed using the Major Depression Section of the Structured Clinical Interview for Depression (SCID) for DSM-IV diagnosis; qualitative interview data were collected on women’s experiences of suicide ideation and plans. Women were assessed two weeks after routine HIV testing as part of Prevention of Mother-to-Child Transmission (PMTCT) screening. Results: Both HIV-positive (49/109) and HIV-negative (60/109) women were assessed. Depression was high (51/109, 46.7%) and equally common amongst HIV-positive and negative women. Suicide ideation was high (30/109, 27.5%) with thoughts of self harm closely linked to suicide plans. Age, previous history of depression and current depression were significantly associated with suicide ideation. Close to equal numbers of HIV-positive and negative women were suicidal. Suicide methods were frequently violent and most women cited family and partnership conflict related to an unplanned pregnancy or their newly HIV-positive status as triggers to their suicide ideation. Conclusions: Rates of suicide ideation among pregnant women testing for HIV are high. Testing HIV-positive causes considerable distress, and among HIV-negative women unplanned and unwanted pregnancies are important risk factors for suicide ideation. Pregnancy brings women into increased contact with the health services with important opportunities for prevention and intervention.