Pulpectomy has emerged as the preferred treatment modality over extraction, for primary teeth with irreversible pulpitis .While hand files have served as the traditional method for paediatric endodontics, rotary instruments offer advancements that can significantly impact treatment in terms of limited chair time thereby lesser operator fatigue, lesser risk of iatrogenic errors (like ledges, zipping canal perforations, etc ) improved canal shaping, reduced post operative pain . Owing to the shape memory and super elasticity of Nickel Titanium(NiTi) rotary files, the challenges faced during biomechanical preparation (BMP) of primary root canals, due to their complex tooth morphology, can now be addressed more effectively. The success of primary tooth pulpectomy relies on instrumentation technique. Recent research shows pediatric rotary systems can substantially shorten pulpectomy procedures. Consequently, rotary systems have contributed to the positive management of child behavior and acceptance towards such a complex and demanding procedure.  Studies have also claimed that uniform BMP by pediatric  NiTi rotary files has decreased  post endodontic pain. The recent shift in paediatric endodontics from sequential multifile rotary systems to single-file systems has facilitated the implementation of single-visit pulpectomy procedures. This innovation is associated with improved obturation quality and enhanced treatment efficiency as measured by reduced operative time. One such file system is the Rotary KEDO-S File System which has been developed exclusively for pulpectomy of primary teeth. This rotary system has evolved over 6 generations The objective of our study is to compare KEDO-S PLUS (fifth generation) and KEDO NANO PLUS(sixth generation) rotary files systems. The KEDO-S PLUS instrument facilitates conservative canal shaping and minimizes the risk of iatrogenic apical perforation during root canal preparation. The most recent rotary single file system is the KEDO NANO PLUS (sixth generation). This heat treated single rotary file with nano carbon coating has a  unique variably variable (VV) taper design which makes it a cutting edge rotary single file system. While many comparative studies have evaluated different paediatric rotary systems with manual K files, none of the studies have compared the efficacy of two different rotary single file systems till date. Also, parental attitudes towards dental procedures influence the behavior of the child undergoing dental treatment. Thus, the aim of our study is to evaluate the instrumentation time, quality of obturation and post-operative pain using two different single rotary file systems. We also aim to evaluate the association between parental anxiety and the child’s behavior during the pulpectomy procedure.