Aim: This invitro study is designed to evaluate and compare the radicular dentinal cracks at various root levels formed by rotary and reciprocating file systems Methodology: The study was carried out on 50 mandibular premolars with single canal which were divided among 3 groups of 15 each as test samples and 1 group served as negative control group consisted of 5 teeth. Access opening of the teeth was done using diamond burs and high speed contra– angle hand piece. Canal length was measured by inserting a size 10 k–file into canal terminus and subtracting 1 mm from this measurement. A glide path preparation was done using 15 k–type files. Apical preparation was completed with size 25 instrument of each system. Bio–mechanical preparation was done using Pro–Taper universal (rotary endomotor) (n=15), Pro–Taper Gold (rotary endomotor) (n=15) and WaveOne Gold (reciprocating handpiece) (n=15) in Group A, Group B and Group C respectively. Teeth in Group D were not instrumented (negative control group) (n=5). Irrigation was carried out using 3% sodium hypochlorite and 9% saline using 27 guage syringe. Teeth were sectioned at 3mm, 6mm and 9mm from the apical end and were observed under the stereomicroscope for dentinal cracks. Results: Statistical analysis was performed using (SPSS) version 16 for windows (SPSS Inc,Chicago,IL). Data normality was checked by Shapiro–wilk test. Intergroup comparison of means between 4 groups i.e. Cracks measurements of different groups were done with the help of ANOVA test. Intergroup pair wise comparison was done using Tukeys post hoc test. Conclusion: ProTaper universal and protaper gold rotary files have tendency to cause more dentinal cracks when compared with Waveone reciprocating system which showed the least number of dentinal cracks at all the levels of root. Both rotary as well as reciprocating file systems tend to generate more stress and thus more dentinal cracks at the apical third in comparison to middle and coronal third