Objectives: The study aimed to evaluate and compare the clinical and radiographic efficacy of Kedo –SG Blue rotary file system versus hand instrumentation using k- files for root canal preparation in mandibular primary molars through 12 months follow up. Materials and Methods: The study was conducted on 40 mandibular primary molars presented in 17 children aged 4 to 6 years using the split mouth technique and were randomly and equally allocated into two groups according to type of instrumentation technique used for root canal preparation, group I (k-file) & group II (Kedo-SG blue rotary files), each group included 20 mandibular primary molars. Time for root canal instrumentation and filling was recorded and overall quality of root canal filling was assessed for all teeth using Technical Scoring System. Clinical and radiographic follow ups for all cases were carried out for 12 months. Results: group II (Kedo-SG Blue) showed statistically significant shorter instrumentation and filling time in comparison to group I (K-file). There were no statistically significant differences between both groups regarding overall quality of root canal filling. Both groups maintained a 100% clinical success rate at 6 and 12 months, but the overall radiographic success rates declined from 90% at 6 months to 80% for group I (K- file) and 85% for group II (Kedo -SG Blue) at 12 months. Conclusions: Kedo- SG Blue rotary file system is an effective and efficient file system for pulpectomy in primary teeth. Kedo - SG Blue rotary file system decrease dental chair side time. Both hand and rotary file systems can achieve equal quality of root canal filling, however, (Kedo- SG Blue) offers a slight advantage in terms of achieving higher quality outcomes, particularly in the 1st primary molars.