Abstract: A typical method, genomic fingerprinting by restriction fragment endlabeling (RFEL-DNA Fingerprinting) for fish was developed and applied toOreochromis mossambicus.Total genomic DNA was digested with a restrictionendonuclease.The fragments were end labeled with α-32p dATP by using theklenow fragment of DNA polymerase and separated by electrophoresis in 6% polyacrylamide/8M urea (sequencing gel).Depending on the different restrictionendonuclease, this method produced well-separated fragments (satellite DNA).Themethod described is a simple, sensitive, stcady and Powerful technique for genotypingfish species.