The principal goal in pediatric dentistry is to retain the primary teeth in the oral cavity until its physiological exfoliation to preserve the arch integrity . The choice of treatment for symptomatic decayed primary teeth is Pulpectomy in which conventionally hand files are used for cleaning and shaping but it is time-consuming and the increased length of the appointment may negatively influence the child’s behavior during the treatment. Therefore, the aim of the study is to assess Instrumentation time and Child’s behaviour after using Rotary, Reciprocating and Hand files in primary teeth using Frankel Behaviour rating in 5 –10 yrs. old patients. MATERIAL AND METHOD: A total of 45 primary teeth were included in the study according to the inclusion criteria. They were divided randomly into 3 groups ( Group-1 Hand files; Group 2- Rotary files; Group 3- Reciprocating files). During each procedure, instrumentation time was recorded using a stopwatch. The pre- and postoperative child’s behaviour was assessed by an evaluator. RESULTS: The analysis was performed by using One Way ANOVA test. A significant difference was found in instrumentation time. The mean biomechanical preparation time was observed to be significantly shorter in the paediatric rotary and reciprocating file groups as compared to hand file group. CONCLUSION: The clinical performance of paediatric rotary and reciprocating files was found to be superior and the choice of file system did not significantly alter behaviour.