Correct classification based on the accurate radiological evaluation is the keypoint in proper management of the acetabular fracture. Interpretation of the radiologic features of the acetabular fracture requires understanding of the relationship between radiologic landmarks and anatomic structures composing acetabulum. The standard radiographic views include acetabular A-P, iliac oblique and obturator oblique views. CT is mandatory for evaluation and provides more accurate informations, such as size and location of the fragment, joint impaction, intraarticular fragment, comminution, dislocation of the femoral head and sacroiliac joint involvement. Combined interpretation of the standard radiographic views and CT is essential. Tomography and 3-D CT provide additional information. Two representative classification systems of the acetabular fracture are Judet and Leteurnal classification and comprehensive classification of AO. Judet and Letpurnal focused on anatomic two columns and two walls, and devided the acetabular fracture into five elementary and five associated fracture types. The elementary fracture types are basically two part and the associated fractures are combination of at least two elementary types and so, they are three or four part fractures. Comprehensive classification system is based on Judet and Letournal classification and follows skeletal AO classification system. It is apprehensive, logic, universal and easy to computerize. Besides, it shows fracture personality which is important prognostic factors. Type A represnets single wall or column fractures, type B tran,iverse oriented fractures, and type C complete articular fracture, namely floating acetaoulum. The sequence in groups under the type is correlated with the prognosis but not always in types.