Fertility traits have been included within breed selection programmes for the Norwegian Red (NR) dairy cow population in Norway for over thirty years. As a consequence, a 60 day non-return rate to first artificial insemination (AI) of 72.5% was recently calculated for NR cows in Norway (Garmo et al., 2008). In view of this long term breeding programme, and current fertility performance within Norway, there is considerable interest in the NR breed as a means of overcoming the high levels of infertility that currently exist within the Holstein-Friesian (HF) breed. However, farming systems within Norway are very different from those within the UK, with herd sizes in particular being much smaller. Thus an experiment was established on 19 commercial dairy farms to compare the fertility performance of cows of the NR and HF breeds.