Seborrheic dermatitis is a chronic, erythemo-squamous disorder affecting between 3 and 11% of the population worldwide. Many factors like sex, age, season, stress and alcohol consumption influence the severity and natural histroy of this common dermatological condition. Our previous study showed that patients with exacerbated seborrheic dermatitis show insufficient and deficient levels of serum 25-hydroxyvitamin D (25(OH)D). In present study we investigated the the correlation between the serum levels of 25(OH)D and the severity of clinical presentation and frequency of reccurences in patients with seborrheic dermatitis. Results showed that patients with more severe skin condition have lower serum vitamin D levels.