Breeding for increased intestinal worm resistance using faecal egg count (FEC) as an indicator trait has been implemented in several sheep industries. The research on which this development is based has been carried out on resource flocks with only limited information on how the same genotype performs under a wide range of conditions. Pollott and Greeff (2004a), using industry Merino data from Australia, have reported genetic correlations between FEC and sheep production traits to be zero. The only exceptions were fat depth (FAT), eye-muscle depth (EMD) which were moderately negatively correlated. Whilst investigating the genotype by environment interactions in this dataset Pollott and Greeff (2004b) described the way in which the heritability of FEC and production traits varied in a wide range of flock environments. This paper reports how the genetic correlations between FEC and production traits vary across a range of FEC environments.