Objectives: The aim of this study was to determine the clinical features of fibromyalgia and its frequency depending on the presence of HLA B35 antigen. Subjects and methods: This study included 66 respondents older than 18 years. Subjects underwent HLA typing during routine diagnostic processing at the Department of Tissue Typing of the Clinical Hospital Center Split. HLA typing was performed in 55 subjects, of which 36 (65.45%) were HLA B35 positive and 19 (34.55%) HLA B35 negative. Data on patients were collected from the medical records of patients treated and controlled at the Department of Rheumatology and Clinical Immunology of the Clinical Hospital Center Split. Data on gender and age of subjects and associated comorbidities and chronic therapy were analyzed. During the routine examination, patients completed a WPI questionnaire to obtain data on the number and location of pain points. They also completed the SSS 2a questionnaire, which collected data on concentration disorders, sleep disorders and the presence of chronic fatigue, and the SSS 2b questionnaire recorded the presence or absence of the most common somatic symptoms associated with fibromyalgia. Results: The study included 60 women and 6 men and the mean life expectancy of HLA B35 + patients was 58.50 years while in the second group it was 51 years. In both groups, a higher number of women than men was recorded. Patients who were HLA B35 positive had a higher incidence of arthritis, and HLA B35 negative patients had a higher incidence of systemic connective tissue disease, psoriasis, and hypothyroidism. The mean number of pain points in HLA B35- patients was 3 pain points higher than in the second group. The frequency and intensity of sleep disorders, concentration and fatigue are higher in HLA B35 patients. The most common symptom in both groups of patients is myalgia with a significantly higher prevalence in HLA B35 negative patients. The most commonly used drug in both groups of patients was ibuprofen. Conclusions: The incidence of fibromyalgia in HLA B35 positive patients is numerically higher compared to HLA B35 negative patients, but without statistical significance. HLA B35 negative patients had more severe clinical features and a higher overall score (WPI + SSS). The most common symptom in both groups of patients is myalgia, the most common comorbidities are joint disorders.