A retrospective, cross sectional study was conducted to investigate potential occupational reproductive hazards from ionizing radiation, chemotherapeutic agents, solvents, and video display terminals among nurses. Questionnaires concerning pregnancy outcome were completed by 663 women employed as oncology nurses, nononcology nurses, and female university employees (comparisons) in three counties in western Washington State. The three groups reported a total of 16 birth defects in the first three pregnancies. One was reported by the university employees (comparison group), seven by the nononcology nursing group, and ten by the oncology nursing group. The oncology nurse group reported significantly more birth defects than the comparison group. The most prominent association observed was an apparent effect of radiation on stillbirths and miscarriages. This was apparent both in second and third pregnancies. The combined effect of radiation and chemotherapeutic agents on miscarriages/stillbirths, and all adverse reproductive outcomes, was strongest for the second pregnancy. Unintentional occupational exposure to radiation posed potentially serious risks for adverse pregnancy outcomes. Nurses have the potential for exposures to ionizing radiation while holding patients for radiographs, and while providing direct patient care to patients during and after nuclear medicine testing and implants.