This experiment was carried out in order to evaluate some technical aspects of the industrial processing of tilapias (Oreochromis spp.), with emphasis on the filefishing profitability in an industry, located in Minas Gerais state, Brazil. During a period between January and November, 2004, 4260 fishes, totalling 2560 kg, with individual weights ranging from 300 to 1000 g (mean individual weight of 600 g) were processed. Data collected comprehended total body weight, and parts weight, such as: head and viscera, filefish, skin, carcass residue and "toilet" residue, aiming to correlating the per cent value of each part, also considering: fish size method of cutting and processing time. The net filefish per cent was 31.0%, ranging between 28.9% to 33.6%, complemented by: head-viscera 36.0%; skin 8.0%; carcass residue 22.0% and toilet 3.0%. No statistical differences in net filefish gains in three different classes of sizes of fishes (300-600 g; 601-800 g and 801-100 g) (P > 0.05) were detected In addition, the variation of net yield, as well as labor efficiency, had a particular impact in the company competitvity.