Aall-A and Aall-B, two novel heterodimeric snake-venom C-type lectin-like proteins (sv-CLPs), were purified from the venom of Deinagkistrodon acutus from Anhui, China. Strikingly, both these proteins can localize on and congregate human erythrocytes, instead of aiming at the common targets of sv-CLPs such as platelet glycoproteins, von Willebrand factors, coagulant factors etc. The crystals of Aall-A belong to space group P2, with unit-cell parameters a = 105.2, b = 56.2, c = 108.7 A, beta = 100.5 degrees , and diffract to 2.0 A resolution, while the crystals of Aall-B belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 36.8, b = 56.5, c = 149.2 A, and diffract to 2.2 A resolution. To our knowledge, this is the first report of sv-CLPs with this unique function and of their preliminary crystallographic analysis.