This study established a murine model for the study of mycotic mastitis. The mammary glands of BALB/c mice were inoculated on the fifth day of lactation with graded doses (10⁴, 10⁵ and 10⁶ cells) of a pathogenic strain of Candida krusei isolated from bovine mastitis. The animals were killed 1, 2, 3, 4, and 5 days after inoculation. In the infected mammary glands, the pathological reaction consisted of primary' infiltration with heterophils and mononuclear cells, focal necrosis, formation of microabscesses, epithelial hyperplasia and some fibrosis. The severity of the changes was dose-dependent and increased with time after infection. An increase in the plasma concentrations of complement factors C1, C3c, C4 and C5, Factor B and alpha-2-macroglobulin suggested that an acute phase response and activation of the complement system had occurred as a result of the infection.