During the last decade the important role of ultrasound in the study of congenital and acquired diseases in Paediatric Orthopaedics is all the more established and reinforced. The early diagnosis and management of hip disorders during the neonatal period, is of great importance. In this period the skeleton is mostly cartilagenous and can be imaged better and more accurately with the use of ultrasound compared to radiography. Moreover, during growth, diseases, such as transient synovitis of the hip, are imaged better by ultrasound than radiologically. In a two year period 2001–2002 ultrasound examination was used in 990 children which presented clinical findings of suspected hip disease, either congenital (mostly DDH), or acquired, such as transient synovitis, Perthes, SCFE and others. Furthermore, of great interest was one rare case of deep venous thrombosis, in a 13-year old girl. The last was diagnosed by ultrasound. In all cases, significant help was provided to the clinical doctor and important information was derived, regarding the differential diagnosis and management. The quality of imaging and evaluation of the ultrasound findings is fundamental for the successful application of the method. The above requirements are established by the experience and scientific sufficiency of the doctor performing the examination.