The seeds of the cotton plant are an important source of food protein. The presence of gossypol in the seeds limits the use of protein isolates as additives to food products. The use of salt and alkaline solutions for extracting the proteins leads to the formation of isolates with relatively high gossypol constants. Extraction in an acid medium permits the presence of the toxin to be excluded. In this process, a number of problems arise which are connected with the presence of a large amount of phytin (about 5%) in the seeds of the cotton plant. The latter affects both the yield of food protein on extraction and functional properties. A method is proposed for eliminating traces of phytin from an acid isolate. A substantial influence of phytin on the properties of the proteins has been observed in those cases where the latter is strongly bound to the proteins at acid pH values.