Objectives: The study evaluated the professional activity of patients after a total cementless hip replacement surgery performed at the age of ≤30 years. Material and Methods: The study group comprised 87 patients, with 95 total cementless hip replacements. The mean age was 25.7 years. The youngest patient was 17 years old, and the oldest 30 years old. The mean length of observation was 20.1 years, ranging 5–33 years. All patients underwent clinical and radiological evaluations before the surgery, and again in the third, sixth and twelfth months after the surgery. Further follow-up visits were performed every year. The tests were scored according to the Merle d’Aubigné and Postel (MAP) classification, as recommended by the Polish Society of Orthopaedics and Traumatology. Postoperative radiographs were used to assess the position of the endoprosthesis, and the degree of implant healing in the bone tissue. The data was subjected to statistical analysis. Results: Of the surveyed group, 67 patients were professionally active before the surgery: 34 were white-collar workers, 29 manual workers, and 4 students or school pupils. The remaining 20 had not worked for many years, and were receiving sickness or disability benefits. An excellent result, according to the Kellgren-Lawrence classification, was noted in 22 cases, a good result in 42 cases, and a satisfactory result in 6 cases. In 25 cases, a poor result was observed. All of the patients professionally active before the surgery returned to work following the procedure. A further analysis found that 15 previously-unemployed patients commenced employment following the procedure. The mean length of the sick leave was 196.2 days, and rehabilitation payments were granted in 5 cases. Conclusions: Total cementless hip replacement is a valuable method of treating osteoarthritis in young patients. All of the patients who worked before the surgery returned to work in the same position and on the same employment conditions. Most of the previously-unemployed patients commenced employment following the procedure. Int J Occup Med Environ Health. 2021;34(6):747–54