The authors describe a case of primary Sjögren's syndrome, which was complicated with severe autoimmune agranulocytosis quite sensitive to immunosuppressive therapy. Agranulocytosis is a very rare complication of this autoimmune rheumatic disease as opposed to leucopenia. A remarkable feature of the presented case is the fact that correct diagnosis of primary Sjögren's syndrome has not been settled for almost 25 years. The disease has manifested only in the form of arthropathy imitating rheumatoid arthritis.