In the following study, a work is conducted to study the effect of internal helical groove that made by using thumbscrew, on the performance of heat pipe using distilled water as working fluid. The helical groove functions as return artery for the condensate that should move from condenser section to evaporator section. With high twist of helical groove the path of condensate is relatively isolated from contact counter vapor flow path. The results show that there is an increase in overall heat transfer coefficient for helically grooved pipe than non grooved one over the tested range of input power. The performance for heat pipe with helical groove pitches 0.75 mm and 1. Mm is better than performance of heat pipe with helical groove pitches 1.25mm and 1.5 mm. Comparison between the present work and correlation from others was done and a trial for correlating the present experimental work, using the same forms of their correlation, was done. Normalization for the results shows that the enhancement in performance ranged from 20% up to 55% in overall heat transfer coefficient for helically grooved pipe than non grooved one over the tested range of input power.