The aim of the presented study was to analyse the causes and incidence of dislocation of hip prosthesis. Aim of the work has been executed based on study material covers the period from 1995 to 2008 which comes from the Clinic of Traumatic Surgery and Orthopaedics with the Rehabilitation Department 5th of the Military Clinical Hospital with Polyclinic Independent Public Healthcare Facility in Cracow. It is a 1514 alloplastics of hip joints. Collectively, in analysed test material dislocation of hip prosthesis was diagnosed in 96 patients, 6,5%, including cement prosthesis in 47 of them, which is 3,2%, non-cement endoprosthesis in 22 (1,5%), partial endoprosthesis in 15, which is 1% and revision replacements in 12, which gives 0,8%. Multiple dislocations were diagnosed in 54 patients. Research methodology was based on an analysis of the data contained in medical records of operated patients and its relation to the dislocations of hip prosthesis and their risk factors. Statistical analysis of result has also been performed. The dependence between the incidence of various types of prosthesis dislocation, and sex, age of patients, indication for prosthesis implementation what is breaking the neck of the femur and hip joint degeneration, the type of surgery (primary or audit) and sometimes being followed by dislocation (up to 3 months and 3 months after surgery). The analysis of quantity and quality of dislocation of the hip prosthesis allows to formulate the following conclusions. Total dislocation of cement prosthesis are most often in people over 75 years, especially among women in who an indication for operation were hip fracture or alleged joints. Dislocation of hip prosthesis is typically during the first three months of surgery performed. In the majority of surgery are the results of receptive disorders that affect the adaptation to new motor conditions. Causes of dislocation of the hip prosthesis are diverse and multi-factorial.