The Nestos Delta is one of the most important wetland in Greece as well as in Europe due to its extent and diverse habitats. It is included in the Wetlands List of International Importance under the Ramsar Convention, belongs to the Natura 2000 Network as well as to the Special Protection Areas of the Birds of the European Union. It is also part of the Eastern Macedonia and Thrace National Park. Intensive agriculture is one of the greatest threats for this important ecosystem. The municipal wastewater reuse for crop irrigation grown in the protected area, appears to be an environmentally acceptable solution for alleviating the natural water shortage, since it could save significant amounts of irrigation water as well as it could reduce the adverse effects of the treated effluents discharge into the aquatic ecosystem. This study describes the plan of reusing the treated wastewater effluent, produced by Waste water Processing Plant of Chrysoupolis Municipality in this ecologically sensitive area, on the basis of climatic factors, and crop irrigation water requirements, grown in the area. Thus, the mean daily and monthly rate of reference evapotranspiration was calculated employing the Penman–Monteith equation according to FAO-56., and the net water requirements for each crop were assessed for the whole irrigation period. The volume of the effluents produced by the wastewater treatment plant of Chrysoupolis could cover 5.0% of the irrigation water requirements.