In order to investigate transport stress on porcine peripheral blood lymphocyte subsets and Th cytokines, blood samples were collected from pigs before and after transport. Creatine kinase (CK), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), glucose, and cortisol in the serum were measured. The number of leukocytes and lymphocytes, percentages of lymphocyte subsets, as well as Th cell cytokines level and their mRNA expression were detected, respectively. After transport, the level of CK, glucose and interleukin (IL)-4 increased significantly (p<0.01), LDH, Th memory cells, natural killer and interferon (IFN)-γ increased significantly (p<0.05), cortisol, number of leukocytes and lymphocytes decreased (p<0.01), percentages of γ δ T cells, naïve Th cells and cytotoxic T lymphocytes decreased significantly (p<0.05). The mRNA expressions IL-2 and IFN-γ were down regulated, p<0.01 and p<0.05, respectively. While IL-4, IL-6, and IL-10 were up regulated, but only IL-10 displayed a highly significant difference (p<0.01). These data suggested that transport could cause immune suppression in pigs, which influences cellular immunity more than humoral immunity, and humoral immunity may play an important role in transport stress. Proper measures should be taken to reduce susceptibility of infection after transport