Most patients are concerned about the anticipated length of service and reasons of replacement of fixed dental prostheses (FPDs). This study tried to find out relationship among various factors causing failures in fixed dental prostheses. Patients treated with fixed dental prostheses were examined clinically and radiographically. A group of 106 patients were evaluated for unsatisfactory restorations. These groups of patients produced records of initial treatment to ascertain the length of service of restoration. The mean survival period of fixed dental prostheses was 7.5 years. This investigation helped find causes for failures and survival period of various FPDs. Among the reasons of failures, caries was the most frequently observed (24.2%), followed by defective margin (18.2%), unsatisfactory esthetics (15.2%), retention problem (11.7%), periodontal disease (8.8%), fractured tooth (10.6%), periapical lesion (5.8%), porcelain fracture (4.2%) and others (1.3%). Causes of failures were also grouped into two groups (Mechanical & Oral diseases) for comparison. The Mechanical group showed higher failure percentage (59.9%) as compared to Oral diseases group (38.8%).