We have previously reported a simple procedure for gene transfection mediated by cationic lipid vesicles for animal cells, in which a commercially available synthetic cationic surfactant, dimethyldioctadecyl ammonium bromide (DDAB), was used for making lipid vesicles. The transfection method was associated with low cytotoxicity and high transfection efficiency. In the present study, the method was applied for gene transfection into quail embryos. The complex solution of lipid vesicles and pmiwZ plasmid, a beta-galactosidase expression vector under the control of beta-actin promoter as a reporter, was injected into quail embryos at various developmental stages using a glass micropipette. After incubation at 37.7 degrees C for 3-4 d, the embryos were fixed and stained with X-gal solution. Under optimal conditions, about 80% of quail embryos expressed beta-galactosidase in limited regions of tissues and organs with high viability. Moreover, 35% of the treated embryos (15/43) hatched following in vitro embryo culture, using the method developed by us.