Unresolved endoplasmic reticulum (ER) stress can lead to cell apoptosis. We therefore tested the role of ER stress in intestinal epithelial barrier disruption in piglets post-weaning. A total of 24 piglets (21 d of age and 6.52 ± 0.29 kg) from 4 litters were randomly continued to be nursed by sows (suckling piglets, 3 piglets/sow) or weaned to a corn and soybean meal–based diet. On d 3 and 7 post-weaning, blood and jejunum tissue were collected at necropsy. Thus, this produced 4 experimental groups (management/time) as suckling/3 d, suckling/7 d, weaning/3 d and weaning/7 d (n = 6/group). Data were analyzed by ANOVA procedure of SPSS including management, time, interaction between management and time as the main factors. Differences between means were determined by using the Duncan multiple comparison method. Weaning stress induced significant elevations in plasma cortisol level, D-lactate content and diamine oxidase (DAO) activity (P < 0.001). Moreover, this management-related increase in blood index was higher in 3 d than in 7 d (P = 0.03 for cortisol, P = 0.03 for D-lactate and P = 0.02 for DAO). Enterocyte apoptosis index in jejunum was increased in weanling piglets (P < 0.001), this alteration was accompanied by increasing jejunal gene expression of caspase3 (P = 0.03), without any difference between piglets at different time. Weaning stress did not affect Bcl-2 expression but decreased caspase9 expression (P = 0.04). Meanwhile, weaning stress upregulated mRNA expression of fas and caspase8 that were related to death receptor signal (P = 0.03 and P < 0.001). Marked weaning modifications were also observed for gene expression of ER stress pathway (glucose regulated protein 78kDa, +16%, P = 0.02; eukaryotic translation initiation factor 2-subunit 1 α, +17%, P = 0.02; activating transcription factor 4, +16%, P = 0.002; x-box binding protein1, −19%, P = 0.004; ER degradation enhance- mannosidase α like 2, −11%, P = 0.10). However, most of these genes were not affected by time or interaction between management and time. In conclusion, weaning stress induced jejunal enterocyte apoptosis and barrier disruption possibly via regulation of ER stress pathway and death receptor signal.