Elucidation of acyl migration was carried out in the Lipozyme RM IM (Rhizomucor miehei)-catalyzed transesterification between soybean phosphatidylcholine (PC) and caprylic acid in solvent-free media. A five-factor response surface design was used to evaluate the influence of five major factors and their relationships. The five factors - enzyme dosage, reaction temperature, water addition, reaction time, and substrate ratio-were varied on three levels together with two star points. Enzyme dosage, reaction temperature, and reaction time showed increased effect on the acyl migration into the sn-2 position of PC, whereas increased water addition and substrate ratio had no significant effect in the ranges tested. The best-fitting quadratic response surface model was determined by regression and backward elimination. The coefficient of determination (R) was 0.84, which indicates that the fitted quadratic model has acceptable qualities in expressing acyl migration for the enzymatic transesterification. Correlation was observed between acyl donor in the sn-2 position of PC and incorporation of acyl donor into the intermediate lysophosphatidylcholine. Furthermore, acyl migration into the sn-2 position of PC was confirmed by TLC-FID, as PC with caprylic acid was observed on both positions. Under certain conditions, up to 18% incorporation could be observed in the sn-2 position during the lipase-catalyzed transesterification.