Nineteen southern African isolates of Plasmodium falciparum were typed by polyacrylamide gel electrophoresis, using 5 enzymes (glucose phosphate isomerase, adenosine deaminase, lactate dehydrogenase, NADP-dependent glutamate dehydrogenase and 6-phosphogluconate dehydrogenase). Limited variation was found amongst the isolates and the frequencies of variants were similar to those of isolates from other parts of the world. Eight of the isolates contained 2 forms of glucose phosphate isomerase, indicating clonal heterogeneity. One of these 8 isolates also contained 2 forms of adenosine deaminase and another showed 2 forms of lactate dehydrogenase.