Estrogen and progesterone receptors were measured in tissues from 43 patients with various uterine sarcomas using the dextran-coated charcoal assay. Estrogen receptor was present in 55.5% and progesterone receptor in 55.8% of samples, at median estrogen and progesterone receptor concentrations of 10.7 and 15.8 fmol/mg cytosol protein, respectively. These median values are much lower than those in 30 consecutive endometrial adenocarcinomas and 50 breast carcinomas assayed in our laboratory. Progesterone receptor status correlated strongly with estrogen receptor status in uterine sarcomas (P = .001). Estrogen and progesterone receptor levels were not influenced by stage, grade, or mitotic count. Patients 50 years of age or less had significantly higher progesterone receptor than those over 50. No such age effect was seen for estrogen receptor. Endometrial stromal sarcoma had higher estrogen and progesterone receptor levels than other histologic types. Low-grade endometrial stromal sarcomas had higher median estrogen receptors (238.9 fmol/mg) and better survival (all patients alive at 6-12 months) than did high grade (N = 7) endometrial stromal sarcomas (median ER = 6.6 fmol/mg, all dead of disease at 8-27 months). For all histologic types, evaluable patients with stage I or II disease (N = 16) were more likely to survive longer than one year than those with stage III or IV disease (N = 13, P = .003). Evaluable patients with estrogen receptor-positive sarcomas were more likely to survive longer than one year than those with estrogen receptor-negative tumors (P = .006). With one exception, an endometrial stromal sarcoma, hormonal therapy exerted no beneficial effect.(ABSTRACT TRUNCATED AT 250 WORDS)