The World Health Organization estimates that 3.1 percent of East African women aged 15-44 have undergone unsafe abortions. This study presents findings regarding abortion practices and beliefs among adolescents and young adults in Tanzania, where abortion is illegal. From 1999 to 2002, six researchers carried out participant observation in nine villages and conducted group discussions and interviews in three others. Most informants opposed abortion as illegal, immoral, dangerous, or unacceptable without the man's consent, and many reported that ancestral spirits killed women who aborted clan descendants. Nonetheless, abortion was widely, if infrequently, attempted, by ingestion of laundry detergent, chloroquine, ashes, and specific herbs. Most women who attempted abortion were young, single, and desperate. Some succeeded, but they experienced opposition from sexual partners, sexual exploitation by practitioners, serious health problems, social ostracism, and quasi-legal sanctions. Many informants reported the belief that inopportune pregnancies could be suspended for months or years using traditional medicine. We conclude that improved reproductive health education and services are urgently needed in rural Tanzania.