Objectives: The aim of this study was to investigate correlation between metabolic syndrome (MetS) and clinical presentation of vulgar psoriasis (PV), including the analysis of the metabolic syndrome components and PV. The primary outcome was to evaluate more severe clinical forms of psoriasis as preconditions for insulin resistance development (IR), irrespective of the MetS presence. Study Design: case control study. Participants: The study included a total of 128 patients divided into two groups of 64 patients. One group consisted of 64 patients with both PV and MetS and the other, control group had 64 patients suffering from PV but without presence of MetS. The two groups were matched in terms of age and gender. Material and methods: For both groups the following data were obtained: demographic, clinical and laboratory data. Severity of the PV and quality of life of all patients were assessed by PASI and DLQI index. The presence of MetS was determined by revised NCEP ATP III definition. For glucose metabolism evaluation, fasting blood glucose, HbA1c, insulin, C-peptide, HOMA-IR and HOMA-B were analysed. Results: Significant presence of MetS was found in patients suffering from PV. Statistically significant MetS presence was found in the group of patients suffering from moderate form of PV. PASI index values were significantly higher in patients with MetS compared to the patients without MetS. Correlation between PASI and HOMA-IR index was extremely strong, persisting even after adjustment for BMI. Correlation between BMI and waist circumference with PV severity was not found, confirming correlation between IR and PV severity form irrespective of obesity. Based on higher HOMA-IR values found in patients suffering from moderate and severe form of PV but without presence of MetS and higher level of HOMA-B index found in patients without MetS, the results indicate that the severity of PV is an independent risk factor for IR, irrespective of the MetS presence and preserved beta-cell function. Conclusion: Severity of PV is the independent IR risk factor in patients suffering from a severe form of PV. One should not ignore patients suffering from PV but without MetS, especially not those suffering from moderate form of PV. It is necessary to perform insulin resistance screening (HOMA-IR) because once MetS has developed, HOMA-IR cannot be considered as an independent predictor of psoriasis severity.