Objective : Pulptomy and pulpectomy usually are the most common techniques used in pulp therapy for primary teeth and despite the relative ease of performing this techniques iatrogenic errors may. furcal perforation of common errors can be occurred during performing pulp therapy in primary molars. two types of furcal perforation were selected according to time factor elapsed since their occurrence ( recent and long standing) and these types of perforation treated with MTA. This study was directed to evaluate the ability of MTA to treat furacal perforation in primary molars regarding the time factor Subjects and Methods: thirty patients were selected 15 with accidently recently ( group A) furcally perforated molars and 15 with long standing old perforation (group B), and the two types sealed with MTA and then completed by conventional pulp therapy treatment either by pulptomy or pulpectomy for group A , and pulpectomy for group B, then they followed up clinically and radiographically for 12 months. Result: there was statistically significant difference in success incidence between the two groups (p=0.014); being higher in recent perforation. For long standing perforation; 10 patients out of 15 patients (66.7%) showed success; while in recent perforation; 15 patients (100%) showed success. Conclusion : recent type of perforation which repaired at the same visit has a higher success rate and better prognosis than old type or long standing in primary molars