Summary Blood samples from a series of persons of Lebanese origin living in Sydney have been tested for 9 blood group, 5 serum protein and 16 red cell enzyme systems as well as haemoglobin types. The Lutheran, Kidd and Colton blood group systems and all the serum protein and enzyme group systems reported on here, except haptoglobin and glucose‐6‐phosphate dehydrogenase, have not been studied previously in Lebanese. There were no cases of glucose‐6‐phosphate dehydrogenase deficiency or abnormal haemoglobins nor were any unusual phenotypes detected in the other 29 systems investigated. In the blood group systems there was a relatively high A1/A2 ratio and low frequencies for the Rh ‐ve and Co(b+) phenotypes, but frequencies in the other systems were comparable with values found in studies of other Middle East or European populations. In the Kell system the possibility exists that the Lebanese may have an appreciable frequency of (K‐k‐). Gene frequencies for die serum protein systems were similar to other Middle East populations where comparable figures are available, and the same is true for the red cell enzyme systems. For glucose‐6‐phosphate dehydrogenase and phosphohexose isomerase, values obtained suggest that frequencies in north India are similar to those in Lebanon. The overall results are discussed in relation to selection in a migrant population.