Boron is widely used in various areas of modern technology. Due to the environmental problems arising during theproduction and use, the studies on the removal and recovery of boron from wastewater have been increased recently.Membrane distillation (MD) system is smaller in size with respect to other common distillation systems and needslower operating temperatures. In addition, the equipment costs are reduced and the safety of the process increasessince it operates at lower pressures. Moreover, the membrane distillation process can remove pollutants from waterwithout using chemicals. In this study, boron rejection from aqueous solutions and wastewater was investigated byusing direct contact membrane distillation (DCMD) system where both surfaces of a porous hydrophobic membranewere in contact with liquid streams. The effects of various parameters (pH, feed concentration, feed temperature, etc.)on boron rejection were investigated and the highest boron rejection was found to be 50 % when pH=10 at 50 °C andwith feeding by a pump of 54 rpm. According to the test results of wastewater from Kırka Borax treatment plants, themean distillate fluxes were found as 13, 16 and 14 L m-2 h-1 at the feed temperatures of 30, 40 and 50 °C, respectively.The boron removal percentages were found to be 47, 64 and 48 % at 30, 40 and 50 °C, respectively. It was observed inthe XRD spectra that the crystals in wastewater mainly consist of Na2B(OH)4Cl and Mg2B2O5 structures.