Introduction: This study was conducted to determine the surface topography of root canal dentin after mechanical preparation using different endodontic file systems.   Methodolgy: Twenty single rooted extracted premolars were used. After teeth decoronation, all roots were divided into four groups (five roots each). Group PNX was instrumented by ProTaper Next files, Group W was instrumented by Wave One. Group P was instrumented by Protaper files, and Group H (control) was instrumented by K type hand files. Radicular preparation for all groups was performed according to the each file system's manufacturer instructions. Roots were split longitudinally in a bucco-lingual direction giving a total of 10 specimens for each group. Samples of each group were photographed at cervical, middle and apical regions of each prepared canal using USB Digital microscope.   Results: Group P showed the highest roughness mean value followed by group H then group PNX while group W recorded the lowest value. The difference between groups was statistically significant. There was no significant difference between group PNX and group W. Apical regions recorded the highest roughness mean value followed by middle regions while cervical region recorded the lowest roughness mean value.   Conclusions: The use of Protaper file system showed the highest root canal roughness while Wave One file system showed the lowest values. Root canal apical regions showed higher roughness mean values than middle or cervical regions in all groups.