In this study, interleukin-6 (IL-6), C-reactive protein (CRP), and haemoglobin levels were evaluated to compare the degree of surgical invasion between mini and standard incisions in total hip arthroplasty (THA). Sixtytwo patients admitted for primary cementless THA were enrolled in this randomised study. The patients were allocated to have surgery through either a mini incision of <10 cm or a standard incision of 15 cm. In each group, inflammatory responses were evaluated by IL-6, CRP, and haemoglobin levels before operation and one day after operation. Significant differences were not found in IL-