Previous studies have found high levels of unintended pregnancy among female sex workers (FSW), but less attention has been paid to their abortion practices and outcomes. This study is the first to investigate abortion-related mortality among FSW across eight countries: Angola, Brazil, Democratic Republic of Congo (DRC), India, Indonesia, Kenya, Nigeria, and South Africa. The Community Knowledge Approach (CKA) was used to survey a convenience sample of FSW (n = 1280). Participants reported on the deaths of peer FSW in their social networks during group meetings convened by non-governmental organisations (n = 165 groups, conducted across 24 cities in 2019). Details on any peer FSW deaths in the preceding five years were recorded. The circumstances of abortion-related deaths are reported here. Of the 1320 maternal deaths reported, 750 (56.8%) were due to unsafe abortion. The number of abortion-related deaths reported was highest in DRC (304 deaths reported by 270 participants), Kenya (188 deaths reported by 175 participants), and Nigeria (216 deaths reported by 312 participants). Among the abortion-related deaths, mean gestational age was 4.6 months and 75% occurred outside hospital. Unsafe abortion methods varied by country, but consumption of traditional or unknown medicines was most common (37.9% and 29.9%, respectively). The 750 abortion-related deaths led to 1207 children being left motherless. The CKA successfully recorded a stigmatised practice among a marginalised population, identifying very high levels of abortion-related mortality. Urgent action is now needed to deliver comprehensive sexual and reproductive healthcare to this vulnerable population, including contraption, safe abortion, and post-abortion care.