Day-old-piglets were passively immunized by vaccinating the pregnant sows with K88ac enterotoxigenic Escherichia coli (ETEC) vaccine. High level of ETEC specific antibodies was excreted in colostrum (3733.33 +/- 1152.13) and maintained a detectable level (100.00 +/- 0.00) up to 21 day post partum (DPP). The IgG was the predominant immunoglobulin followed by IgA and IgM. Piglets born of vaccinated dam (group A) and unvaccinated dam (group B) were challenged in 7 day of age. Clinical and faecal scores were significantly (P < 0.01) low in group A than that of group B. Piglets of group A developed mild diarrhoea (33.33%), while all the control piglets developed profuse diarrhoea and 3 of these died before 14 day of challenge infection.