Brucellosis is an endemic zoonosis in our country and a common worldwide problem. Brucellosis can hold on different systems. Clinical signs and symptoms are not specific in this disease. Osteoarticular involvement pattern is the most common complication but spondylodiscitis is rare. Wright tube agglutination is the most common serologic test in the diagnosis of brucellosis. Prozone phenomenon is a false negative response resulting from high antibody titer which interferes with formation of antigen- antibody lattice, necessary to visualize a positive flocculation test. In this article, we present a case of late diagnosis of brucellar spondylodiscitis due to prozone phenomenon.