Multivariate statistical analysis and geographic information systems were used to delineate Idaho into homogeneous agroclimate zones for the purpose of applying successful dryland agricultural research practices and management decisions throughout these areas of relative climatic uniformity. Data used to produce the classification are from the Parameter-elevation Regressions on Independent Slopes Model (PRISM), developed at Oregon State University. PRISM has produced gridded estimates of mean monthly and annual climatic parameters from point data and a digital elevation model (DEM). Principal components analysis was performed on 55 variables including various temperature and precipitation parameters, the number of growing degree days, the annual number of freeze-free days, the annual day of freeze in the fall, and the annual day of freeze in the spring. Cluster analysis identified 16 agroclimate zones in the state each having similar climatic conditions regardless of it’s spatial location. As a result, successful dryland agricultural practices and management decisions that are based on new technologies and developed for one part of the state may potentially be applied to other parts of the state that fall within the same agroclimate zone.