Tilapia production has increased in Aguamilpa Reservoir, in Nayarit, Mexico, in the last few years and represents a good economic activity for rural communities and the country. We determined growth parameters, mortality and reproductive aspects for 2 413 specimens of blue tilapia <span name="style_italic">Oreochromis aureus </span>in this reservoir. Samples were taken monthly from July 2000 through June 2001, of which 1 371 were males and 1 042 were females. Standard length (SL) and total weight (TW) were measured in each organism. The SL/TW relationships through power models for sexes were determined. The growth parameters <span name="style_italic">L <span name="style_sub">∞</span>, k, </span>and <span name="style_sub">∞</span>, k, <span name="style_italic">t<span name="style_sub">0</span> </span>of the von Bertalanffy equation were estimated using frequency distribution of length through ELEFAN-I computer program. Finally the reproductive cycle and size of first maturity were established using morph chromatic maturity scale. The results suggested that the males and females had negative allometric growth (<span name="style_sub">0</span> <span name="style_italic">b</span>&lt;3). Significant differences were found between SL/TW model for the sexes, suggesting separate models for males and females. Results indicate that there are no differences in growth rates between sexes; the proposed parameters were <span name="style_italic">L<span name="style_sub">∞</span></span>=43.33cm standard length, <span name="style_sub">∞</span><span name="style_italic">k</span>=0.36/year and <span name="style_italic">t<span name="style_sub">0</span></span>=-0.43years. Natural and fishing mortality coefficients were 0.83/year and 1.10/year, respectively. The estimated exploitation rate (0.57/year) suggested that during the study period the fishery showed signs of overfishing. Blue tilapia reproduces year-round; the highest activity occurs from January through May and size of first maturity was 23cm SL. We conclude that it is necessary to establish a minimum catch size in this reservoir based on the reproductive behavior of this species. Rev. Biol. Trop. 58 (4): 1577-1586. Epub 2010 December 01.<span name="style_sub">0</span>

growth; reproduction; exploitation rate; Oreochromis aureus; Aguamilpa Reservoir; ELEFAN