We examined the association between the somatotype and its main components (endomorphy, mesomorphy and ectomorphy), and the prevalence of several chronic diseases. The data were obtained from a cross-sectional survey designed to assess somatotype and morbidity with special reference to most often diagnosed diseases. The study population comprised 524 men and 250 women. The subjects underwent laboratory tests and clinical and anthropometric examinations. Of all examined workers, 94.8% fell into the five somatotype categories; of these, 394 were endomorphic mesomorphs. The most common somatotype was endomorphic mesomorph for men and mesomorph-endomorph for women. In five disease groups, prevalence was significantly related to a somatotype. Mesomorphic endomorphs most frequently suffered from digestive system diseases (40.6%, p < 0.05), neuroses (30.1%, p < 0.05), and radiculitis lumbosacralis (15.4%). The prevalence of arterial hypertension in mesomorph-endomorphs (37.1%), endomorphic mesomorphs (35.5%), and mesomorphic endomorphs (34.3%) was equal. In both genders, those with the highest endomorphy and mesomorphy and the lowest ectomorphy, grouped by cluster analysis, were those who suffered most frequently from arterial hypertension and liver disease. The authors conclude that the somatotype having a dominant mesomorphy and marked endomorphy constitutes a risk factor as a particular predisposition toward certain diseases and requires body weight control.