The aim of research has been the estimation of a proliferative potential as simultaneous detection of a proliferative cells number (Ki-67 index) and duration of mitosis (nucleolar argyrophilic protein expression--B23/nucleophosmin and C23/nucleolin) at patients with adrenocortical cancer. In according to lifetime of patients after operation 2 groups had been sorted out. The first one included patients surviving 56.12 months, the second one--9.25 months. We've found out that different aspects of tumor diagnosis as well distinction of benignant or malignant tumor growth, a malignant degree of tumors, a prognostic criteria of illness, survival of patients etc. must be characterized by total research both a proliferative cells fraction (Ki-67 index) and a rate of mitosis (expressions of B23/nucleophosmin and C23/nucleolin).