Micrurus spixii venom was studied after fractionation by Sephadex G-100 SF gel filtration chromatography. Several enzymatic activities and biological effects were investigated in whole venom and fractions. The venom was resolved in four peaks in a range of about 73.2-10.7 kDa molecular weight. Alkaline phosphatase and acetylcholinesterase activities were found in peak I, and procoagulant activity was seen in peak II. Phospholipase A2, hemorrhagic, and proteolytic activities were detected in peak III. A second procoagulant factor and proteinase were present in peak IV. Thrombin-like enzyme and direct hemolytic activities were not found in any assayed samples.