The protonation constant values of different four triazole derivatives have been determined in ethanol %50 – water %50 mixtures by spectrophotometric methods. The electronic absorption spectra of different four triazole derivatives at various pH values at 190-400 nm intervals were recorded. The calibration of the electrode system was done potentiometrically by Gran’s method. Data were calculated using the linearization method with Henderson-Hasselbach equation. The obtained results are in good accordance with potentiometric values.