Inhibition of precipitation in counter current electrophoresis was at least 32 more sensitive when compared to the normal counter current electrophoresis for the demonstration of mink antibodies against Aleutian disease virus (ADV). ADV antigen can be produced from mink organs or in cell culture. The reactivity of the two types of antigen in the two kinds of counter current electrophoresis methods is described in this report. When 22 mink sera were titrated in normal counter current electrophoresis against cell culture produced antigen and organ produced antigen, significantly lower antibody titres were found with cell culture produced antigen. The difference was not found when inhibition of precipitation of counter current electrophoresis was used.