The study was carried out to compare the fatty acid profile and related lipid nutritional indices in the breast and thigh meat of two slow-growing lines of chickens La Belle (LB) and Bresse Gauloise (BB) and their crosses (♂LBx♀BB, ♂BBx♀LB). The birds were reared indoors in the experimental poultry farm of the Institute of Animal Science –Kostinbrod, Bulgaria. At the age of 12 weeks, 6 male chickens of each line were slaughtered and lipid analysis of the breast and thigh meat was done. The differences in the fatty acid profile and related nutritional indices of the meat between the lines were assessed by one-way ANOVA. The fatty acid composition was affected by the crossing of the lines but to a different extent in breast and thigh meat. The highest amount of monounsaturated fatty acids (MUFA) was observed in the meat of ♂BBx♀LB chickens due to the significant increase of C16:1n-7 in breast and C18:1n-9 in the thigh of these birds. On the other hand, this crossbred line exhibited the lowest levels of polyunsaturated fatty acids (PUFA). Furthermore, the lowest content of MUFA was observed in the breast of the pure lines and thigh in BB and ♂LBx♀BB, while the highest PUFA level was determined in the breast of LB and thigh of ♂LBx♀BB. The differences in the meat dietetic quality described by the lipid indices showed no consistent patterns in the pure and crossbred lines depending on the type of meat. When compared with the rest, the breast meat of the LB male chickens showed significantly higher polyunsaturated/saturated fatty acids (P/S) ratio, while lowest n-6/n-3 PUFA and thrombogenic index (TI). The values of the atherogenic index (AI) and the ration between the hypo-and hypercholesterolemic fatty acids (h/H) were also improved in this line. Thigh meat however, showed best characteristics in terms of P/S and n-6/n-3 in the ♂LBx♀BB cross.