Feed intake (FI) of sows during lactation is a serious problem because sows require a large amount of energy for high milk production during lactation. Providing a palatable diet is important for lactating sows to cope with the stress of breast-feeding. Palatability can be increased by adding sweeteners to diets. This study was conducted to evaluate the effects of saccharin (sweetener) on growth performance, fecal moisture, and litter performance of lactating sows. Sixteen sows were randomly allotted to one of two dietary treatments in a 27-day trial starting from lactation. The two dietary treatments were supplemented with 0 and 0.2% saccharin (sweetener), respectively. Average daily feed intake (ADFI) was increased (p < 0.05) and back fat loss (BFL) was decreased (p < 0.05) in sows fed saccharin supplementation diets compared with sows fed control diet during lactation. However, sows’ body weight loss, body condition score (BCS), fecal score, and the number of piglet survival were not different (p > 0.05) among dietary treatments. The two dietary treatments also had no significantly different effect (p > 0.05) on litter weight and average daily gain (ADG) of piglets. Taken together, saccharin has no significant effect on growth performance of piglets but it can increase FI and reduce BFL of lactating sows.