This paper proposes a detailed low frequency noise (LFN) parameter extraction method for high-voltage (HV) MOSFETs at low (50 mV) and medium (3 V) drain biases. In V-d = 3 V region, noise coming from the channel is dominant while in linear region there is an extra contribution of noise from the drift region part especially for long-channel devices in strong inversion region. Flicker noise of 50 V and 20 V N- and P-channel HV-MOSFETs was measured over a large current range from weak to strong inversion, making possible the extraction of the noise parameters related to the different noise contributions, such as mobility fluctuations in low current regime, carrier number fluctuations and Coulomb scattering in medium and high current regime. In some cases, series resistance noise contribution especially at high current is apparent as well. The parameter extraction procedure is devised for a recently established charge-based flicker noise model for HV-MOSFETs. Noise parameters related to the carrier number fluctuation effect in the gate oxide extension in drift region are also extracted in high current regime of long-channel devices under low drain bias condition. The frequency exponent AF related to the slope of the measured noise spectra is also extracted. Measurements and analysis include both long as well as short N- and P-channel HV-MOSFETs. (C) 2014 Elsevier Ltd. All rights reserved.