We report on species variation in the venoms of the three species of death adder; the Common death adder (Acanthophis antarcticus), the Northern death adder (Acanthophis praelongus) and the Desert death adder (Acanthophis pyrrhus). The venoms were found to vary in their biochemical (chromatography) and biological (PLA(2) activity, anticoagulant activity and reactivity with commercial death adder antivenom) properties. Each species produced significant differences in the profile and distribution of PLA(2) activity, when whole venom was applied to a cation-exchange Mono-S column. PLA(2) enzymes were purified from each venom and termed acanthoxin B (from A. praelongus), acanthoxin C (from A. pyrrhus) and the previously characterised acanthoxin A (from A. antarcticus). Acanthoxin B and C showed lower enzymatic activities than acanthoxin A (4.0, 13.7 and 23.9 micromol of phospholipid hydrolyzed/min/mg protein, respectively). N-terminal sequencing revealed acanthoxin B to share highest homology with the numerous PLA(2) isozymes (Pa-12C, Pa-1G, Pa-12A) from the King brown snake (Pseudechis australis) and Acanthin I from the Common death adder. Similar to acanthoxin A, acanthoxin C showed highest homology with Acanthin I/II, and pseudexin A-chain from the Red-bellied black snake (Pseudechis porphyriacus). Whole venom from A. antarcticus, A. praelongus and A. pyrrhus each showed weak anticoagulant activity (being able to prolong coagulation of the plasma for 107, 220 and 195 s, respectively). By immunodiffusion, each venom produced precipitation bands against commercial death adder antivenom.