In this study, the possibility of animal species determination of meat used in heat-treated sausages was demonstrated. For this purpose, sausages made from pure beef, pork and horsemeat and mixtures of two or three of these species were heated at 75 degrees C for 15 min. In pherograms of sausages made from pure beef, pork and horsemeat, differences that distinguish these three species could easily be determined by their staining densities and positions. It was determined in pherograms of mixtures that were prepared by adding horsemeat and pork to beef in defined rates that protein bands characteristic for beef kept their intensity while the intensities of the bands typical for pork and horsemeat had decreased. In pherograms of sausages that contained a large amount of horsemeat (50 and 40 %), the determination of bands IV and VI, which are characteristic for horse, lead to the identification of horse meat in the mixture. Below these mixture rates, down to 5 % horsemeat and pork mixed into beef sausages, it was concluded that the sausage was not made from only beef by determination of band VI which was darker compared to beef sausage.