Introduction Periarticular muscles have a significant role in keeping the mobility and integrity of the hip joint. The aim of this article was to investigate the effects of the total hip arthroplasty and early rehabilitation on the muscle strength. Patients Three groups of examined persons (matched in relation to musculosceletal conditions, sex, age and occupation) were included in the investigation. The first group (40 of the involved hip) and the second group (with 33 involved hips) were groups of patients with late-stage of osteoarthritis of the hip. The first group of patients was managed conservatively and the second group operatively (total cemented hip endoprosthesis was performed). The third group was control group with 123 healthy hips. Material and methods The maximal voluntary isometric strength was measured with dynamometer. The muscle strength was tested in all three groups: in the first group of patients at the beginning and at the end of the therapy and in patients of the second group 6?3 months postoperatively. Results A significant improvement of the muscle strength was noted for the flexors (t=2.45, p<0.05), musculus tensor fasciae latae (t=2.35, p<0.05), extensors (t=2.85, p<0.01), adductors (t=3.02, p<0.01), external rotators (t=3.1, p<0.01), m. gluteus medius (t=5.28, p<0.001) and internal rotators (t=5.77, p<0.001) after total hip arthroplasty and early rehabilitation in comparison to the conservatively treated group. Conclusion The muscle strength in the patients with osteoarthritis of the hip after arthroplasty was significantly higher than after rehabilitation for all hip muscles but did not reach values of the strength of the muscles in the corresponding control group.