There is disclosed an improved process for producing high purity antihemophilic factor concentrate from an antihemophilic factor-containing dispersion or solution isolated from blood plasma or a blood plasma fraction, wherein the improvement is in carrying-out two consecutive precipitations using a combination of precipitants in each precipitation, first a combination of 1-4% by weight, based on weight of solution, of polyethylene glycol and 0.1-0.2 ml of 1-3%, based on weight of suspension, aluminum hydroxide suspension per gram of protein in the starting dispersion or solution, followed by a combination of added polyethylene glycol to provide a final concentration of 9-13% by weight, based on weight of the resulting solution, and 10-20% by weight of glycine, based on weight of the polyethylene glycol solution, and 10-20% by weight, based on weight of the polyethylene glycol solution, of sodium chloride.