Venoms of the Australian elapid snakes Austrelaps superbus and Pseudechis colletti were analyzed in an electrofocusing column. A. superbus venom, little studied in the past, was found to have a mouse i.p. lethal potency of 0.48 mg/kg and to contain at least four lethal components. Venoms of both species had relatively high direct hemolytic activity for washed rabbit erythrocytes, as contrasted with venoms from 23 other species of snakes that were not hemolytic under the conditions used. Among venoms of the same 25 species, those of A. superbus and P. colletti produced turbidity in diluted egg yolk, those of Bungarus caeruleus and Bungarus multicinctus were quantitatively less active on egg yolk, whereas venoms of the 21 remaining species were negative. The component of the venoms responsible for egg yolk reactivity was partially purified and the preparations obtained were strongly active when tested with diluted egg yolk or with erythrocytes. Thin layer and paper chromatographic studies showed that these preparations possessed phospholipase B activity for phosphatidylcholine, lysophosphatidylcholine, phosphatidylethanolamine and phosphatidylserine, but sphingomyelin was not degraded. The results suggest that hydrolysis of phosphatidylcholine is responsible for both egg yolk reactivity and hemolysis.