Life history features of the Cladocera Simocephalus expinosus were examined at ambient room temperature in the laboratory at three different food concentrations of Saccharomyces cerevisiae: high food (12 x 10⁵cells/ml), intermediate food (65 x 10⁴cells/ml) and low food (5 x 10⁴cells/ml). Culture media and food were renewed each day. As food level increased, there was a reduction in the age at maturity. Early reproducing females at larger sizes are accompanied by the production of larger broods which generate an important number of neonates per reproductive female. On the contrary, when food level diminished, there was an increase in the age at maturity. Later reproducing females at smaller sizes induced smaller broods and consequently, generate a lesser number of neonates.