A preliminary study was conducted to investigate the effects of palm kernel expellers on productive performance, nutrient digestibility, and changes in white blood cells (WBC) of lactating sows. A total of 14 sows (200 ± 12 kg BW; 2.5 parity) were randomly assigned to 2 dietary treatments: a diet based on corn and soybean meal (CON) and CON + 20% palm kernel expellers (PKE). Sows were fed the treatments for 28 d (weaning) after farrowing. Blood was collected from each sow and randomly selected 4 piglets in each sow before farrowing or on d 3, 7, or 14 of lactation. Sows were fed respective treatments containing 0.2% chromic oxide from d 15 to 21 of lactation. Fecal samples were collected daily for the last 3 d after the 4-d adjustment period. Measurements were performances and WBC changes of sows and litter, nutrient digestibility of sows, and daily diarrhea of litter. Data were analyzed using the PROC GLM procedure of SAS. The statistical model for every measurement except frequency of diarrhea included dietary effect and parity as a covariate. The chi-squared test was used for the frequency of diarrhea. Sows fed PKE had greater ADFI (7.38 vs. 7.10 ± 0.06 kg/d; P < 0.05) and lost less BW (−6.85 vs. −8.54 ± 0.51 kg; P < 0.05) and backfat depth (−0.42 vs. −0.71 ± 0.09 mm; P < 0.05) than those fed CON. However, there were no differences on digestibility of dry matter, nitrogen, and energy and weaning to estrus interval of sows fed either CON or PKE. Piglets from sows fed PKE gained more BW (203 vs. 181 ± 7.62 g/d; P = 0.08) and had less frequency of diarrhea (6.80 vs. 8.56%; P = 0.07) than those from sows fed CON. However, no difference was found on preweaning mortality of piglets from sows fed either CON or PKE. Sows fed PKE had lower number of WBC (9.57 vs. 11.82 ± 0.83 × 10³/μL; P = 0.09) before farrowing than those fed CON, but no difference on d 3 and 7. Similarly, piglets from sows fed PKE had lower number of WBC (7.86 vs. 9.80 ± 0.62 × 10³/μL; P < 0.05) on d 14 of lactation than those fed CON, but no difference on d 3 and 7. In conclusion, PKE increased ADFI and decreased changes of BW and backfat depth of lactating sows compared with CON, but no differences were found on other measurements.