Process for the preparation of polyamides comprising the steps of A) reacting a soybean oil condensate obtained from the deodorization of refined soybean oil and which contains less than 30% by weight of free and esterified oleic acid based on the total weight of free and esterified fatty acids in said condensate, with a C.sub.1-4 alkanol in the presence of a zinc oxide catalyst to convert free fatty acids and fatty acid glyceride esters to fatty acid C.sub.1-4 alkyl esters;B) removing excess C.sub.1-4 alkanol, volatile reaction by-products, water, and the zinc oxide catalyst from the resulting reaction mixture;C) heating the reaction mixture from step B) under vacuum to obtain a distillate of fatty acid C.sub.1-4 alkyl esters;D) separating the distillate from step C) into a fraction containing mostly C.sub.16-18 saturated fatty acid C.sub.1-4 alkyl esters and a second fraction containing mostly C.sub.16-18 unsaturated fatty acid C.sub.1-4 alkyl esters wherein the oleic acid C.sub.1-4 alkyl ester content is less than about 35% by weight thereof;E) dimerizing said second fraction in the presence of montmorillonite clay; andF) reacting the dimerized second fraction with a polyamine.