Abstract: An electrophoretic karyotype of Acanthamoeba polyphaga has been preliminarily analysed by means of pulse field gel electrophoresis (PFGE).Ten chromosomal DNA bands are distinguishable on the gel.Using yeast (Saccharomyces cerevisiae) chromosomal DNA as size standard,we estimate the size of the chromosomes to be between about 200 kilobase pairs (kb) and 2 megabase pairs (mb).