The objective of the work presented here was to investigate the influence of genotype-environment interaction on genetic correlations. In our theoretical models we have considered plant populations consisting of random samples of lines from chromosome-doubled haploids produced from F 1 gametes, highly inbred SSD-lines, and clones of randomly breeding populations grown in two and multiple environments. The results of our theoretical considerations are that if genotype-environment interaction exists, great differences are expected to occur in the estimates of genetic correlation coefficients obtained in different environments. Based on the variance and covariance components for genotype-environment interaction we suggest a new type of correlation coefficient, called genotype-environment correlation, r ge . Our theory has been applied to several series of experiments. Estimates are presented from two series, both of which demonstrate clearly the consequences of genotype-environment interaction on the genetic correlations.