The aim of this study was to present our experiences in diagnosing spondyloarthritides (SpA), and to list the most common clinical features of HLA-B27 positive patients. The study included 65 HLA-B27 positive patients with confirmed diagnosis of ankylosing spondylitis (AS) and psoriatic arthritis (PsA) who were analyzed between 2009 and 2010 in Clinic of Internal Medicine in Osijek. The diagnosis of seronegative spondyloarthritides was based on the ASAS (Assessment in AS Working Group) classification criteria for axial and then supplemented with ASAS criteria for peripheral SpA and was confirmed by radiological techniques. For diagnosing the ankylosing spondylitis (AS), there have been applied the modified New York criteria. Radiological criteria for definite sacroiliitis according to the modified New York criteria is bilateral sacroiliitis, grade 2-4 (> or = 2) or unilateral sacroiliitis, grade 3-4. For diagnosing the psoriatic arthritis (PsA), there were used CASPAR diagnostic criteria. Other features of SpA are defined within the existing classification criteria. HLA-B27 antigen was determined by direct immune-fluorescence technique using flow cytometer. The average age of patients was 50.34 years, of whom 27 female (41.53%), 38 male (58.46%). Duration of illness was 15.79 years on average. With 75.38% of patients, there had been determined the diagnosis of AS; 24.62% of patients had the diagnosis of PsA. The most common clinical characteristics that patients had were: inflammatory back pain (pain Inflammation along the lumbosacral spine), peripheral arthritis, intermittent pain in the gluteus, sacroiliitis, enthesitis, uveitis, dactilitis.