Abortion is illegal in Thailand unless the woman's health is at risk or pregnancy is due to rape. This study, carried out in 1999 in 787 government hospitals, examined the magnitude and profile of abortion in Thailand, using data collected prospectively through a review of 45,990 case records (of which 28.5% were classified as induced and 71.5% as spontaneous abortions) and face-to-face interviews with a sub-set of 1,854 women patients. The estimated induced abortion ratio was 19.5 per 1,000 live births. Almost half the induced abortions were in young women under 25 years of age, many of whom had little or no access to contraception. Socio-economic reasons accounted for 60.2% of abortions. Serious complications were observed in almost a third of cases, especially following abortions performed by non-health personnel. Government physicians' current provision of induced abortion went beyond the provisions of the law in almost half of cases, most commonly for intrauterine death and for congenital anomalies. The paper proposes a framework for policy discussions of the grey areas of maternal and fetal indications leading to legal reform, in order to facilitate safe abortion. A recommendation to amend the abortion law has been proposed to the Ministry of Public Health and the Thai Medical Council.