Psoriasis is a complex immunological disease with several comorbidities. Thus several genes related to immun system was recognized as disease susceptibility genes. On the other hand, the conserved mechanism that triggers both psoriasis and comorbidities are important to identify the common physiology of diseases. Thus, in this study, the prevalence and distribution of the eNOS Glu298Asp polymorphism among psoriatic patients were evaluated. 114 psoriatic patients, who gave informed consent, were enrolled in the study. The genotype frequencies for eNOS gene polymorphism were determined by melting curve analyses (Real time PCR). In consistency of genotype frequencies (biallelic markers) with the Hardy-Weinberg equilibrium was tested using a Chi-Square test on a contingency table of observed versus predicted genotype frequencies. Sixty two patients (54.4%) had the genotype Glu/Glu (wild group) and 52 (45.6%) patients a mutant genotype, Glu/Asp (46 patients, 40.4%) or Asp/Asp (6 patients, 5.2%). The genotype distribution were consistent with Hardy-Weinberg equilibrium for psoriatic groups (χ²calculate: 0,496 1st degree). We could not found any differences between allelic distribution or genotype frequency of eNOS Glu298Asp gene polymorphism and psoriasis.