CERVUS is a Windows 95-based program designed for large-scale parentage analysis using co-dominant loci. Analysis is broken down into three sequential stages. Using genotype data in text file format, the program can analyse allele frequencies, run appropriate simulations and carry out likelihood-based parentage analysis, testing the confidence of each parentage using the results of the simulation. Simulations may also be used to estimate the power of a series of loci for parentage analysis, using real or imaginary allele frequencies.