Signal characterization using the capacitive measurement method is studied on the effect of frother dosage in the two-phase column flotation process. The aim of the study is to characterize the signal on the effect of frother dosage. A laboratory flotation column with 0.05?m diameter and 1.25?m height is used for the experiment. Frother of methyl isobutyl carbinol (MIBC) with the concentration of 1-50?ppm is used as a frother and the air injection from 1 to 5 liter per minute (l/m) is given to each frother dosage. All experiments use distilled water to maintain the purity of water since its purity affects the electrical properties. The results show that the capacitive signals as a function of time with and without the frother are different, in which the fluctuation of the process without frother is higher and it appears more frequent than with the frother, especially the difference is clearly seen at the air injection of 2.5 l/m. Furthermore, the capacitive signal decreases as the frother dosage increases. This occurs because the more frother dosage tends to produce more bubble which can decrease the capacitive signal. Based on this result, the effect of frother dosage can be characterized using the capacitive measurement method. Therefore, it has a potency to be developed as the process control and monitoring technology in the field of the flotation process.