P-channel MOSFET parameters measured at 300 K, 77 K, and 4.2 K are discussed; these include I-V characteristic curves, channel conductance, transconductance, threshold voltage, field effect mobility, and forward and reverse p+n junction characteristics. Some qualitative explanations of the dependence of the data on temperature and substrate doping concentration are given. Interesting LHe phenomena are highlighted and discussed in terms of accepted solid state models.