Abstract Vitamin C (VC) is involved in many biological processes including immune response. This experiment was conducted to investigate the effects of supplemental VC on the development of mink lymphocytes in wild type (Standard genotype mink) and animal model of Chediak-Higashy (CH) syndrome (Sapphire genotype mink). Chediak-Higashy syndrome is genetically determined disease of human and animals affecting morphology and functions different cells including leukocytes. Using morphometry and cytochemistry methods, we reveal that VC supplementation (100 mg/animal/day) induces lymphocyte activation in wild type mink and CH-like mink. However, the effect of VC supplementation is sex-related and depends on the genotype of mink. In general, we obtained data that VC supplementation neutralizes genotype-related size differences among lymphocytes.