Background: Total hip arthroplasty is the most common surgery performed for complications of hip hemiarthroplasty. Hemiarthroplasty has been a good method of treating displaced fracture neck of femur. With the increased demands placed on the prosthesis by highly active patients, the failure rate increased following hemiarthroplasty. Pain is the most reliable complaint that indicates failure. Pain may be due to many complications related to hemiarthroplasty as loosening, sepsis, protrusio, dislocation, and periprosthetic and prosthetic fractures. Conversion to total hip replacement is a good method for treating patients with painful hemiarthroplasties. Objective: This study aimed to evaluate the result of revision total hip replacement after failed hemiarthroplasty. Patients and Methods: This is a retrospective study included 62 patients with ages ranged from 38 years to 75 years with a mean (62.7±11.38), with the conversion of failed hip hemiarthroplasty to total hip arthroplasty between 2000 and 2015 with a minimum follow up 5 years and maximum follow up 10 years at Zagazig University Hospital. Males represented 54.8% (34 cases) and females were 45.2% (28 cases). Results: Our study that the mean Harris hip score significantly increased from 21.87±8.31 preoperative to 74.21±18.3 postoperative P=0.00** and postoperative radiologically we find that 58 patients (93.5%) has fixed implants and 4 patients (6.5%) has loose implants. Conclusions: This present study showed that the conversion of failed hemiarthroplasty to THR is a good way of treatment for painful hemiarthroplasties. Conversion is a complicated surgery with a higher rate of complications both intra and postoperatively.