The hyperimmunoglobulinemia D syndrome (HIDS), so-called mevalonate kinase deficiency, is caused by recessive mutations in the gene encoding mevalonate kinase enzyme. HIDS is characterized by recurrent fever attacks of 3-7 days that begin in infancy and recur every 4-6 weeks. The febrile period is accompanied by lymphadenopathy, arthralgia, abdominal pain, diarrhea, aphthous ulcers, and varying degree of skin involvement. The course and severity of the disease may be quite different. There is no effective or proven therapy for HIDS. We report two cases with HIDS, which had separate clinical findings and treatment strategies.