The aim is to study the combined effects of heavy metals and antibiotics on the genetic cell apparatus, to assess the possibility of correction of the genotoxic effect of the immunomodulator. Using Ford-Hamerton method the cytogenetic effects of the antibiotic Ceftriaxone (450 mg / kg) on the background of cadmium chloride (1 х 10-3M), lead acetate (1 х 10-3 M) and imunofan (0.004 mg/kg) were estimated on marrow cells of 102 male rats of Wistar population. Results. Imunofan showed antimutagenic effect: the number of chromosomal aberrations compared with the negative control (1.5 ± 0.50) % decreased 3 times (0.50 ± 0.29) %; the genome protection coefficient (Fp) was 66.67 %. The expression coefficient of the mutagenic effect of Cd (II) is 3.5 units, the number of chromosomal aberrations - (5.3 ± 0.91)%; the expression coefficient of the mutagenic effect Pb (II) was 3 units; the number of chromosomal aberrations - (4.5 ± 0.85) %; p < 0.001. Ceftriaxone in the maximum therapeutic dose had mild mutagenic properties: the expression coefficient of the mutagenic effect -2.2 units; the number of chromosomal aberrations (3.3 ± 0.73) %. In the variants [Pb (II) + ceftriaxone] and [Cd (II) + ceftriaxone], the mutagenic effect increased in comparison with the mono-effect of substances: the expression coefficient of the mutagenic effect, respectively 3.9 and 4.1 units; the number of chromosomal aberrations - (5.86 ± 0.95) %; p