Abstarct: The studied karstic aquifers are located in north of Northern Khorasan province and Kopedagh zone. Arnaveh, Rezghaneh and Sarani are the most important springs in this area that their annual discharge volumes are much lower than the annual recharge volumes. This study aims to reveal the groundwater origin and catchment area of the major karstic springs in this area by hydrogeological, hydro geochemical and isotopic techniques and hydrogeological balance. Precipitation and spring samples were collected during the course of a year from October 2016 to September 2017. The pH, electrical conductivity (EC) and discharge (Q) of these springs were measured in situ. The concentration of the major ions, heavy mextals, stable isotopes (18O, 2H, 13C, 37Cl) and radioactive isotope (3H) in rain waters and study springs were measured. First, the catchment areas of the springs were mapped by geological method and then verified by other methods. The recharge percentage in study area varies from 20% to 50%. catchment areas of the Arnavah, Rezeganeh, Sarani and Ghordanlu Springs are 160, 70, 5.6 and 5.4 km2, respectively. The sum of annual discharge volume of the springs is about 25 mm3, which is far less than the annual recharge volume in the limestone formations of this area (about 120 mm3). The dominant hydro chemical processes are carbonate and gypsum dissolution and direct ion exchange. The time series of discharge, temperature, electrical conductivity and ions concentration with little variations indicat diffuse flow system. The following formula was drawn as the local meteoric water line (LMWL) δ2H = 7 × δ18O + 6.32 with higher slope and intercept values in summer and lower values in winter. The isotopic composition of precipitation is directly related to temperature and inversely correlated with moisture content and precipitation. The isotopic composition of precipitation has the positive relationship with the atmospheric temperatures and the negative relationship with the air humidity and precipitation amount. The winter precipitations are the main source of recharge water to springs and the higher d-excess and the lower isotopic values of these winter precipitations can be ascribed to moisture of Mediterranean origin. The origin of all study karstic springs is meteoric water. The Sarani, Rezghaneh, Ghordanlu and Ayoub springs are depleted in δ18O and δ2H relative to the Arnaveh samples, indicating that the catchment area of these springs is situated at higher elevations. Arnaveh spring has higher isotopic value due to lower elevation of recharge area and evaporation process and it is mainly recharged from old snow. The δ13CDIC values can delineate carbon origin in this area which is carbonate dissolution. The more depleted δ13CDIC values of the Arnaveh, Rezghaneh, Ghourdanlu and Ayoub hot springs are related to the greater soil CO2 contribution. The 37Cl isotope results show that the Sarani spring with the lowest δ37Cl isotopic content has higher degree of karst development in comparison to other springs. Also, the tritium isotope value confirms the low degree of karst development and diffuse flow system in the study area.