Whipple’s disease is a rare chronical multisystem disease caused by the gram-positive microorganism Tropheryma whipplei. The disease is characterized by a long prodromal period and a chronic course. Whipple’s disease is fatal without ethiotropic treatment. But the treatment is prescribed, the outcome is favorable. Because of extremely variable and nonspecific clinical features, patients with Whipple’s disease have lots of complaints. These patients’ treatments are begun by various specialties. All of the foregoing lead to low clinical alertness and make a significant difficulty to the correct diagnosis. We described of case report of Whipple’s disease diagnostic and treatment in a 48-year-old man who was admitted to Novosibirsk State Regional Clinical Hospital in hematology department. He had unknown etiology lymphadenopathy. The diagnosis was confirmed by using endoscopy and pathomorphological examination of duodenum mucous biopsy, biopsy of cervical and intraperitoneal lymph nodes.