This study was conducted to investigate the effects of dietary fat inclusion to create two energy levels on reproductive performance, milk compositions and blood profiles in lactating sows. Twenty-four multiparous sows were randomly assigned to four treatments according to a 2×2 factorial arrangement. Two energy levels (3365 and 3265 kcal/kg) were created by supplementing different fat levels (high and low). Higher energy level resulted in less (P<0.05) body weight and backfat loss, shorter wean-to-estrus interval, and greater body weight gain of piglets. Sows fed higher fat diet had higher (P<0.05) fat concentration in colostrum. Higher concentrations of triglyceride and creatinine and lower concentrations of luteinizing hormone at weanling were noted (P<0.05) in sows fed lower energy diet than those fed higher energy diet. In conclusion, feeding of higher energy diet during lactation may improve the reproductive performance of sows during lactation.