Morphological and statistical analysis was done of deaths caused by neoplasms in the populations of the communities Gródek and Tykocin on the basis of autopsies carried out in the years 1982-1986. The content of magnesium was determined also in the arable layer of soil in these communities. The proportion of deaths from malignancies in the analysed autopsy material was nearly threefold higher in the Gródek community (27.67%) than in the Tykocin community (9.87%). The Gródek community had nearly twice as much (49%) sandy soils with low magnesium content as the Tykocin community (24%). The prevailing malignancies in the Gródek community were in males aged 51-60 years mainly in the digestive tract (61.3%) and respiratory system (22.3%). Histological structure was in most cases that adenocarcinoma and squamous cell carcinomas.