The present investigations aimed at the determination of the effect of liming and magnesium treatment of the soil with elevated heavy metal concentration levels on the occurrence and harmfulness of the beetles and larvae of sitona (Sitona sp.) and broad bean seed beetle (Bruchus rufimanus Boh.). The field experiment was set up in two series: on the unlimed and limed soil. In each series broad bean plants (Vicia faba L. ssp maior), white Windsor c.v. were also grown in the control soil (with natural levels of heavy metals content); in the soil contaminated with heavy metals, doses corresponding to the 1st level of pollution according to ISSPC classification and in the soil contaminated with heavy metal receiving magnesium fertilization. Magnesium fertilization applied in the soils polluted with heavy metal polluted positively affected broad bean growth. Sitona beetles were feeding more eagerly on the plants growing in the control soil with a natural content of heavy metals. Liming positively influenced a decrease of areas damaged by the pest feeding. A loss of an assimilative area due to the sitona feeding was very low and did not exceed 2%. Sitona larvae injured between 16 and 36% of broad bean verrucasan on average. Broad bean seed beetle injured between 13 and 26% of broad bean seeds. No significant influence of magnesium treatment and liming was found in the soil with elevated heavy metal concentration levels on the harmfulness of beetles and larvae of sitona and broad bean seed beetle.