Changes in the components of the hemogram respond to the influence of living and working conditions. The goal is to assess blood parameters, vitamins B12 and B9 in men of mental work. A random sample of blood was collected from men permanently residing in Krasnoyarsk (n = 58). We assessed the degree of anthropogenic load and working conditions according to the degree of harmfulness and danger. A clinical blood test was performed, and the state of the body’s nonspecific adaptive reactions was assessed using lymphocytes. Vitamins B12, B9, and iron were determined. In terms of intellectual, emotional stress and work schedule, the work is harmful (3.3). Signs of anemia were revealed (decrease in erythrocytes in 12.1 %, hemoglobin in 10.3 %, hematocrit in 10.3 %), macrocytic (average erythrocyte volume increased in 10.3 %), hypochromic (reduced average hemoglobin concentration in erythrocyte in 22.3 %), developing due to deficiency of vitamin B12 (in 67.2 %) and B9 (in 32.8 %), iron (below the median in 51.7 %). The proportion of rod-nuclear neutrophils was reduced, the proportion of eosinophils (in 13.8 %) and monocytes (in 25.6 %) was increased, indicating sensitization, allergization, a decrease in nonspecific defense mechanisms and the presence of an inflammatory reaction in the body. The presence of stress in the body was evidenced by indicators of nonspecific adaptive reactions of the body (reactivation in 27.6 %), an increase in the proportion of monocytes in 25.6 % of those examined. It can be assumed that an environmentally unfavorable living environment and hard work in conditions of inadequate provision of the body with cyanocobalamin, folic acid and iron negatively affect the composition of the blood, which, in turn, can affect health.