In this increasingly advanced era, many manufacturers are doing food forgery by mixing food with ingredients that contain pork. The purpose of this study was to determine the differences in protein profiles of beef, pork and processed meat products such as reference meatballs and commercial meatballs. The method that were used in this study was laboratory experimental using SDS - PAGE (Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis). Data were analyzed after gel was colored, gel was observed visually and analyzed descriptively. Data were calculated by linear regression to determine molecular weight. The results showed the difference of protein band and protein between the sample of cow and pig and its processed. Samples of beef contain 16 ribbons, pork 12 ribbons, meatballs references 2-9 bands and commercial meatballs 1-2 bands. Specific protein bands is troponin I with MW 24.5 KDa in beef, whereas in pork there is a specific band of actinin α with MW 97,7 KDa. Desmin, Eu actinin and actin protein bands are detected in all reference meatballs but α actinin is present in only a few samples of pork and beef meatballs. In commercial meatballs there is desmin with MW 57.5 KDa, and there is one protein band found only in pork on sample B.1 with MW 63 KDa.