The aim of the present study was to identify a set of reference genes to be used for normalizing qRT-PCR from ovine whole blood. We designed 11 PCR assays for commonly employed reference genes belonging to various functional classes and then determined their expression level in whole blood samples from control and disease-stressed sheep, both separately and combined, in order to select genes whose stability was unaffected under stress conditions. The geNorm and NormFinder applets [1, 16] were used for validating the reference genes; sample processing and experiments were carried out according to the Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) guidelines [17] .