Introduction World literature data indicate the involvement of inflammatory cells in the pathogenesis of palmar fascial fibromatosis. However, there are no data on possible changes in peripheral blood leukocyte indices in patients with Dupuytren's contracture (DC) in comparison with healthy people.Aim To assess the diagnostic significance of neutrophil-lymphocyte (N/L) and lymphocyte-monocyte (L/M) indices of peripheral blood in patients with CD.Materials and methods 162 medical records of patients admitted for surgical treatment were retrospectively studied. To compare the results of their peripheral blood tests with the norm, anonymous leukocytograms of 110 apparently healthy individuals (control) were used.Results In the group of healthy people and in patients with DC, sexual dimorphism of the absolute content of neutrophils was expressed. In DC males, a statistically significant decrease in the absolute content of lymphocytes (p = 0.05) was found, and in females, a significant increase in the absolute content of monocytes (p = 0.00) compared with the control, while in patients with DC there was no gender-related difference in these indicators, typical for healthy people. N/L ratio was elevated in DC males compared with controls (p = 0.05) and a subgroup of DC females (p = 0.01), but according to the results of ROC analysis, N/L ratio turned out to be diagnostically useless. For the model "L/M – degree of contracture" AUC 0.945, CI 0.918-0.970, p = 0, Se 90.12, Sp 93.21; optimal threshold L/M 3.102. In patients with low L/M (≤ 3.0), the frequency of lesions in both hands and the frequency of grade III-IV contractures are higher by 27.75 % (p = 0.02) and 27.15 % (p = 0.03), respectively than in the high L/M subgroup.Discussion The multidirectional changes in the content of lymphocytes and monocytes in males and females is consistent with the literature data on dual gender-specific ways of regulating the immune system in healthy people and in patients with various diseases.Conclusion The findings of the studied sample of patients show that the lymphocyte-monocyte index is a useful additional laboratory indicator for identifying a risk group for severe fascial fibromatosis. It can be used in clinical practice at no additional cost along with the well-known Dupuytren diathesis criteria to identify a risk group for progression of Dupuytren's contracture.