The experiments described in this paper were designed to measure some of the genotype-environment interactions in peas and the emphasis has been upon the characters which are of importance in relation to the time of maturity, uniformity of maturity and to yield.Six pea varieties were grown at four sites in Eastern England, there being an early an d a late sowing at each site The data were analysed by means of regression techniques and by the analysis of variance. Linear responses t. environment were demonstrated for all the characters in the majority of varieties and the relative importance of somo of the components of yield in different environments were determined. The variation could be partitioned into ite genetic, environmental and interacting components and genotype-environment interactions were demonstrated fos every one of the characters investigated.