The post-natal composition of biliary lipids in the bile of suckling goat kids has been studied during the first month of life. Samples of hepatic and vesicular bile were obtained from animals fed with milk. Bile flow increased with age and the concentration of bile acids also rose up to 14 days of age. Cholesterol reached maximum values immediately after birth and then decreased. Bile acids conjugated with taurine predominated and this pattern of preferential tauroconjugation persisted at all ages, as has also been found in carnivores and sheep. Comparison of vesicular and hepatic bile composition revealed a poor concentration capacity of the gallbladder in pre-ruminant kids.