In Mexico ethinylestradiol (ETE) and levonorgestrel (LEV) are regularly produced and utilized for birth control by women. In this work, we tested the effect of both hormones on the life table demography (LTD) of the rotifers Anuraeopsis fissa and Brachionus calyciflorus, exposed to different concentrations of mixed LEV and ETE in a ratio of 5:1 (500/100, 250/50, 125/25, 62.5/12.5, 31.25/6.25 for the rotifers but with an additional level of 15.625/3.125 mu g L-1 for B. calyciflorus). We also tested the effect of these endocrine disruptors on the population growth rate of A. fissa. Our results showed that significant differences with respect to the control in the lower concentrations of the hormones corresponding to 31.25/6.25 and 62.5/12.5 mu g L-1 of LEV/ETE. Among the life history variables of A. fissa, the average lifespan and net reproductive rate were stimulated by the mixed hormones at 31.25/6.25 of LEV/ETE. Both gross and net reproductive rates and the rate of population increase per day of B. calyciflorus were stimulated by the higher levels (250/50 and 500/100 mu g L-1) of endocrine disruptors.