We describe here the use of PCR-generated templates incorporating T3 polymerase sites in order to prepare digoxigenin (DIG)-labelled cRNA probes against any gene of known sequence. This method was applied to the preparation of probes specific for chicken glyceraldehyde-3-phosphate dehydrogenase messenger RNAs and we demonstrate that such probes can be used for in situ hybridization (ISH). This technique therefore represents a rapid and convenient means to prepare DIG-labelled cRNA probes for use in a non-radioactive ISH. It adds speed and convenience of probe preparation to the previously described advantages of non-radioactive detection techniques.