The influence of intercalated hydrogen concentration on the physical properties ofNbSe3is investigated. The mass-spectrometric analysis reveals a nonlinear dependence of hydrogen extraction from the crystal structure on the saturated pressure. Resistive measurements make it possible to study the concentration dependence of the temperatureTCDWcorresponding to a phase transition accompanied with the formation of a charge density wave (CDW) and temperature dependence of CDW pinning threshold fields. A metal-semiconductor phase transition is observed for certain concentrations of intercalated hydrogen. All the measurements are made in the temperature range of the first CDW transition (90–300 K). ©1997 American Institute of Physics.