DNA primer sets were developed for the amplification of complete mitochondrial genomes for both European and American lobsters in 4 suitable-sized segments. Optimal conditions for polymerase chain reaction routine screening were established. The 4 segments were screened with 24 restriction endonucleases in a test population sample, covering the whole distribution of the European lobster, and restriction patterns of each enzyme were revealed. A segment of 3000 bp comprising part of cytochrome oxidase I gene, the genes cytochrome oxidase II and III, subunits 6 and 8 of ATPase, subunit 3 of the NAD dehydrogenase, and various transfer RNAs, was found to be the most polymorphic. A number of enzyme patterns in each segment differentiated European and American lobsters. Extra bands were observed, indicating heteroplasmy phenomena, which were verified with various approaches. Furthermore, a primer set that enables 1-step ampli fication of the complete mitochondrial genome of the European lobster was established.