Intensive culture of frogs is one of the most complicated forms of aquaculture, Standard management techniques for laboratory or commercial culture are being developed. Tadpole density is one of the most important factors to consider when rearing anurans. The experiment was performed on Rana perezi tadpoles to test the effects of density on growth and metamorphosis. Effects of larval density were examined by subjecting tadpoles to four different densities (1, 5, 10 and 20 larvae l(-1)). Density affected growth rate, weight at metamorphosis, survival and duration of larval stage. Results agree with previously known relationships for ranids: at higher densities developmental time is longer, mean size at metamorphosis is smaller, and mortality is higher. There are clear benefits in rearing R. perezi larvae at low densities (5 larvae l(-1)).