The purpose of the study was to assess the length control of an electronic apex locator-controlled handpiece on using different nickel titanium rotary systems Forty extracted teeth were used. The teeth were divided into two main groups according to type of rotary nickel titanium systems: Protaper file and Revo-S file. Each group was further divided according to the type of irritants: Saline and Sodium hypo chlorite. Working length was established using stereo microscope. Electronic length and auto reverse length were calculated using Dentaport ZX. Results revealed that measurements differences were non-significant when using either Saline or Sodium hypochlorite and measurements differences were non-significant when using either ProTaper or Revo-S file. Saline and sodium hypo chlorite using different rotary files did not affect the accuracy of Dentaport ZX.