The relationship between depot-medroxyprogesterone acetate (DMPA), and other injectable contraceptives and cervical neoplasia was reviewed mainly on the basis of three studies: the WHO Collaborative Study of Neoplasia and Steroid Hormone Contraceptives (2,009 cases and 9,583 controls collected in several, mainly developing, countries); a study of 369 cases of carcinoma in situ, 133 of invasive cancer and 646 controls collected by the National Tumor Registry of Costa Rica; and a cooperative study of 759 cases of invasive cervical cancer and 1,430 controls from four countries in Latin America (Costa Rica, Peru, Mexico and Colombia). There was no evidence of an appreciably elevated risk since most relative risks for ever users ranged from between 0.8 and 1.4, nor of consistent duration-risk relationship which was observed only in one study. The relative risk estimates for longest duration of use ranged from between 0.9 and 2.4. The data are still compatible with the absence of a causal association and with a moderately increased risk (up to a factor 1.5), which finds some biological plausibility as it is in agreement with the overall evidence of the relation between oral contraceptives and cervical neoplasia.