Abstract: In this study, the physico-chemical properties of hot spring water of Bursa province and Erikli cold water were investigated. Erikli cold water is bottled for commercial use. Water samples were collected in-situ for testing and some physical measurements were carried out. Other major analyses were carried out in the geothermal laboratory. Water samples were evaluated by both field observations in-situ and also geological and petrographical observations. Data collected were evaluated by using Aqua-Chem software program in consideration of field observations and the geology and petrography of the sampling area. Data obtained from Aqua-Chem and field observations of the sampling area in consideration of geology and petrography were used for interpretations of hot water samples and cold spring water. Consequently, water samples were characterized according to sources of magma or meteoric waters with the aid of isotope studies and cation and anion data. Also, information on water circulation leading to water-rock interaction where the water passes the Bursa Geothermal system helped the interpretation. The water sample radioactivity results were shown to be within acceptable limits. Water resources were determined for Bursa province and vicinity using Piper diagram. Waters in Cekirge, Kaynarca, Kükürtlü, Zeynine, Dumbuldek, and Inegol Oylat contain Ca-Mg-Na-SO4, Na-Ca-SO4, Na-Ca-HCO3-SO4, Ca-Na-Mg-SO4, Na-Ca, Ca-SO4-HCO3 ions respectively.