Abstract 1. 1. Blood group specific glycoproteins of A, B, H and Le a specificity were prepared from crude ovarian cyst fluid by density gradient ultracentrifugation. 2. 2. The glycoproteins were examined by the methods of sedimentation velocity and equilibrium density gradient ultracentrifugation. 3. 3. No significant correlation was observed between the analytical results for the glycoproteins and the blood group specificity of the cyst. 4. 4. Nearly all the glycoproteins contained more than one species of molecules.