The study carried out on 28 white Wistar adult female rats, divided in four groups: one control and three experimental, exposed in drinking water for six months to 25 ppm Cr VI – LOAEL (E1), 50 ppm Cr VI - 2XLOAEL (E2), 75 ppm CR VI - 3XLOAEL (E3), pointed out: significant (p<0.01) increase of sexual cycle duration comparative to control group and over the physiological limits, in direct correlation to exposure level; modification of sexual stages regularity: significant decrease of sexual cycles percentage with proestrus, estrus and diestrus in physiological limits as duration comparative to control group and inversely correlated to exposure level; appearance of sexual cycles with absent proestrus and estrus directly correlated to exposure level and of prolonged diestrus, directly, significantly (p<0.01) correlated to exposure level.