In this work, the impact of water type on borate ore flotation was investigated, while various physical parameters during flotation were considered in order to compare the results. Two different colemanite samples from Emet deposits of Turkey, named as Emet-A and Emet-B contained 44% B 2O 3 and 40% B 2O 3, respectively. The flotation tests were performed at feed particle size range of −210 +20 μm. Optimal consumption values for the reagents were determined as 2000 g t −1 for AeroPromoter R825 from Cytec Company, a sulphonate type collector, 1500 g t −1 for Procol CA927 from Allied Colloids Company, a sulphosuccinamate type collector and 100 g t −1 for AeroFrother 70 from Cytec Company, an alcohol-type frother. In the tests, the impeller speed of the Denver-type flotation machine was set to 1200 rpm and the samples were fed into a litre cell at 25% solid/liquid ratio and at natural pH value of the slurry at room temperature. The flotation results obtained from the tests with use of tap water, demineralised water and the artificial water prepared with Ca 2+ and Mg 2+ cations deliberately added into demineralised water were compared to each other in optimal flotation conditions.