The calculations used in the preparation of seven new ASHRAE psychrometric charts are described. A brief introduction is given to the thermodynamic property formulation for moist air developed by A. Wexler and R.W. Hyland at the National Bureau of Standards in ASHRAE Research Project RP-216. Definitions of humidity parameters and other properties are given, arid copies of the seven psychrometric charts prepared using the new property formulation are included.