The galactose elimination capacity (GEC) of rats fed low protein liquid diets and libitum with 5% or 0.5% of the energy as protein was compared with that of a control group receiving a similar diet with 25% of the energy as protein. The daily dietary energy intake was almost identical in the three groups. The rats fed the 5% protein diet showed slightly higher GEC than the control group. In the rats receiving the 0.5% protein diet, GEC was significantly decreased to approximately half of the control values and the hepatic protein content was reduced to the same extent. Body weight and liver weight showed reductions to approximately 75% of control values. Triglyceride content in the livers was increased five times in the protein depleted rats. The results indicate that GEC in rats deprived of dietary protein is determined by the amount of hepatic protein.