Chronic periodontitis, which is the major cause of tooth loss in adults, is characterized by a chronic inflammation of periodontal tissues mainly caused by infection with subgingival gram-negative, anaerobic bacteria. Cellular responses in periodontitis are mediated, in part, by bacterial lipopolysaccharide (LPS), which activates monocytes to express of cytokines, growth factors, and procoagulatory factors via LPS receptor CD14. The aim of this study was to determine whether the functional polymorphisms in the promoter of the CD14 gene are associated with the risk of chronic periodontitis and the severity of the disease. Two polymorphisms located in the promoter region (C(-159)T and G(-1359)T) were analysed by PCR and RFLP methods in a group of 135 patients with chronic periodontitis, and in 207 age- and sex- unrelated randomly selected control subjects. The CD14 allele and genotype distributions were similar between patients and controls. However, the frequency of the G allele of the G(-1359)T polymorphism was higher in patients with severe disease than moderate disease. The homozygous genotype (GG) of this polymorphism was found to be significantly increased in the severe patient group. Allele and/or genotype frequencies of the C(-159)T polymorphism did not differ significantly between severe and moderate periodontitis patients. However, we detected a tendency for an increased frequency of the -159 TT homozygotes in severe patients (19.2%) compared with the moderate subgroup (8.3%). In one patient, we identified a new mutation (28-bp deletion) in the promoter of the CD14 gene (del from -1310 to -1337), which occurred in a heterozygous combination. This study demonstrates that a specific genetic marker, which was previously associated with an increased sCD14 level, may act as a disease modifier of chronic periodontitis in the investigated population.