The relationship between occupational exposures and the risk of pregnancy-induced hypertension (PIH) was investigated in a cohort of 5,605 enlisted active duty military women who gave birth during a 2-year period of time. A panel of experts, unaware of disease status, classified the women's job titles as "high," "medium," or "low" for a variety of occupational exposures. PIH was identified through hospital discharge ICD-9 diagnosis codes. Nulliparas were found to have a significantly increased risk ratio (RR) for PIH (RR = 2.3) compared with parous women. Nulliparas employed in jobs involving high levels of physical activity were at significantly decreased risk of PIH compared to nulliparas working at low levels of physical activity (construction craftsmen, RR = 0.37; unskilled laborers RR = 0.71). Occupational exposure to hazardous chemicals was not related to risk of PIH. Although the study results are limited by aggregate exposure classification, they suggest no adverse influence of occupational exertion and a possible beneficial role among nulliparas.