Background: Self-poisoning (overdose) is the commonest form of self-harm cases presenting to acute secondary care services in the UK, where there has been limited investigation of self-harm in black and minority ethnic communities. London has the UK’s most ethnically diverse areas but presents challenges in resident-based data collection due to the large number of hospitals. Aims: To investigate the rates and characteristics of self-poisoning presentations in two central London boroughs. Method: All incident cases of self-poisoning presentations of residents of Lambeth and Southwark were identified over a 12-month period through comprehensive acute and mental health trust data collection systems at multiple hospitals. Analysis was done using STATA 12.1. Results: A rate of 121.4/100,000 was recorded across a population of more than half a million residents. Women exceeded men in all measured ethnic groups. Black women presented 1.5 times more than white women. Gender ratios within ethnicities were marked. Among those aged younger than 24 years, black women were almost 7 times more likely to present than black men were. Conclusion: Self-poisoning is the commonest form of self-harm presentation to UK hospitals but population-based rates are rare. These results have implications for formulating and managing risk in clinical services for both minority ethnic women and men.