An innovative system based on the time domain reflectometry TDR principle for the measurement of liquid level and interface is presented in this paper. The application of time domain reflectometry in liquid level monitoring is relatively recent and most promising due to the achievement of very high levels of accuracy and repeatability and to the substantial advantages over traditional sensors used for level sensing. After a brief review and description of the operating principle and a comparison to traditional techniques, the system is described with the results obtained using water as a sample liquid and water and diesel fuel to show the system capability of detecting liquid-liquid interfaces.