An efficient and simplified method for hand-rearing of Caesarean-derived infant rabbits under gnotobiotic condition was devised. The Caesarean-derived infant Dutch or Japanese-White rabbits and their hybrids (F1; Japanese-White female x Dutch male) were reared in sterilized vinyl-isolators by hand-feeding with two kinds of milk diets, A and B, consisted mainly ofa commercial milk powder for dogs and cats (Esbilac) supplemented with several minor components (Table 2) and administered intragastrically once a day through a Nelaton's catheter. Bacteriological examinations revealed that feces and urine were sterile for the first three days. On the third day, Escherichia coli, Staphylococcus epidermidis, Streptococcus faecalis, Bacillus subtilis, Enterococcus, and Bacteroides sp. were given with milk diet and the infant rabbits were reared until 10 to 12 weeks of age. The weaning rate at 5 weeks of age and the raising rate at 3 months of age were approximately 78% and 77%, respectively (Table 3), indicating that feeding once-a-day with a milk diet mainly composed of Esbilac is suitable for the hand-rearing of infant rabbits. There was, however, no significant difference milk diet A and B on the weaning rate.