Abstract: Drinking cold water in winter is detrimental to the growth and development of post-weaning piglets.Thus, a system providing the piglets with warm drinking water at 26℃(ranging 24.5-26.6℃) in a scale-up swine farm was installed for the study. Changes on the growth and immunity of the piglets were monitored. The results indicated that the total bacteria and Escherichia coli counts in the warm drinking water for the treatment were significantly lower than those in the cold water for control. The average daily weight gain of the piglets in the treatment group was significantly higher than that of control by 4.15% (P < 0.01). The daily feed intake of the treatment piglets was significantly higher than that of control by 7.76%(P < 0.05). Whereas, the incidents of diarrhea in the treatment piglets were merely 43% of that incontrol group. There were no significant differences observed on the levels of IgG, IgM, IgA, porcine circovirus and classical swine fever virus antibodiesin the piglets between the treatment group and control (P>0.05). It appeared that the consumption of warm drinking water in cold weather could significantly improve the growth, without negatively affecting the immunology, of the post-weaning piglets.