Abstract: Apparatus and method for measuring the moisture content of a material, particularly a tobacco material, in which a microwave signal is divided between first and second signal paths, said first path comprising a sampling capacitor, the dielectric of which comprises the said material, and said second path comprising reference delay means, signals from each of the paths being fed to a phase detector providing an output indicative of waveform time displacement of one of said signals relative to the other of said signals. Advantageously signals from each of the said paths are fed through substantially identical first and second limiting amplifiers directly to the said phase detector. A second microwave signal of a frequency different from, but close to, that of the first-named microwave signal may be mixed with the signals from the sampling capacitor and from the reference delay means, the resultant beat signals of lower frequency being fed to the phase detector.