Background/Purpose: Hydatid disease of the spleen is a rare disease, and it occurs in 1%to 8%of all children with hydatid disease. That difference in frequency depends on the social and economic status of the patients and the country. The aim of our study is to reveal its diagnosis and treatment. Methods:From 1985 to 2004, 152 children with hydatid disease have been operated on at the Surgical Department of General and Pediatric surgery at the Medical University in Stara Zagora and Medical University in Plovdiv, Bulgaria. Of the 152 children,15 (9.87%) had spleen localization: 6 males and 9 females,aged 10 to 18 years. A solitary cyst in the spleen was found in 10 patients, 8 children had an isolated cyst only in the spleen, 7 with involvement of other organs (5 in the liver, 2 in liver andlungs). All spleen cysts were “silent.”Abdominal sonography,computed tomography, and enzyme-linked immunosorbent assay tests proved the diagnosis. All children were operated on.Results: A splenectomy was performed in 14 cases, and a cystectomy was possible in only 1 case. Patients with combined forms successfully underwent different variations of cystectomy:6 omentoplasty, 5 capitonnages, and 4 invaginations.Conclusions: Splenic involvement of hydatid disease has no specific clinical manifestation, the diagnosis is late and often leads to splenectomy. Organ-preserving procedures are possible only in cases with early diagnosis. It has to be suspected in a patient with a splenic cyst and has to be confirmed by ultrasonography and/or computed tomography,magnetic resonance imaging, and immunologic tests. The early diagnosis is a good precondition for better results. Background / Purpose: Hydatid disease of the spleen is a rare disease, and it occurs in 1% to 8% of all children with hydatid disease. That difference in frequency depends on the social and economic status of the patients and the country. The aim of our study is to reveal its diagnosis and treatment. Methods: From 1985 to 2004, 152 children with hydatid disease have been operated on at the Surgical Department of General and Pediatric surgery at the Medical University in Stara Zagora and Medical University in Plovdiv, Bulgaria Of the 152 children, 15 (9.87%) had spleen localization: 6 males and 9 females, aged 10 to 18 years. A solitary cyst in the spleen was found in 10 patients, 8 children had an isolated cyst only in the spleen, 7 with involvement of other organs (5 in the liver, 2 in liver and lungs). All spleen cysts were “silent.” Abdominal sonography, computed tomography, and enzyme-linked immunosorbent assay tests proved the diagnosis. All children were operated on. Results : A splenec Patients with combined forms successfully underwent different variations of cystectomy: 6 omentoplasty, 5 capitonnages, and 4 invaginations. Conclusions: Splenic involvement of hydatid disease has no specific clinical manifestation , the diagnosis is late and often leads to splenectomy. Organ-preserving procedures are possible only in cases with early diagnosis. It has to be suspected in a patient with a splenic cyst and has to be confirmed by ultrasonography and / or computed tomography, magnetic resonance imaging, and immunologic tests. The early diagnosis is a good precondition for better results.