Properties of fats are determined by the composition and position (sn-1,2,3) of fatty acids in the fat molecule. Palmitic acid is one of the most atherogenic fatty acids in the sn-2. Interesterification will change the position of palmitic acid in the fat molecule. This study aimed to determine the effect of interesterification on the atherogenic properties of fat. The fat used was beef, extracted by dry rendering, and chemically interesterified using a Na-methoxide catalyst for 20, 30, 60, 90, and 120 minutes. The melting point of the fat was measured using a melting point apparatus then given to guinea pigs. For 21 days, the propyl lipid was measured using the enzymatic method using a micro lab 300 spectrophotometers. The melting point of beef fat from interesterification for 60 minutes was constant, meaning the reaction was complete. Interesterification of beef fat showed an increase in atherogenicity seen from the increase in total cholesterol, triglyceride, LDL and decreased HDL levels after interesterification, respectively 69.20 ± 20.24; 68.60 ± 18.81; 40.43 ± 15.18; 14.33 ± 3.01 mg/dl compared with no interesterification 62.27 ± 16.02; 62.87 ± 14.08; 37.84 ± 13.41; 11.80 ± 2.15 mg/dl (ANOVA, P < 0.05).