A study was carried out to assess the feasibility of monitoring the exposure of barn owls (Tyto alba) to an anticoagulant rodenticide, flocoumafen, by analysis of residues in regurgitated pellets following consumption of flocoumafen‐contaminated mice. Mice were fed on a diet containing [14C]flocoumafen, equivalent to 12 mg kg−1, and killed 24 h later. A single [14C]flocoumafen‐contaminated mouse was fed to each of four captive barn owls, equivalent to 0·11‐0·23 mg kg−1 per bird, followed on seven successive days by control diet (i.e. undosed mice). The [14C]flocoumafen dose was eliminated by the owls over the eight‐day period in pellets (44%, range 35–55%) and faeces (18%, range 11–21%), with the highest residues being observed in samples from the first 24‐h period. Further detailed analysis of the pellets confirmed that flocoumafen residues in the first‐day pellets represented 15% (range 8–26%) of the original flocoumafen residues ingested by the barn owls. Calculations based on these data and typical flocoumafen residues in live captured rodents (following baiting) confirm that pellet residue analysis is a sensitive and appropriate method for the non‐invasive monitoring of exposure of barn owls to flocoumafen. There were no symptoms of anticoagulant poisoning in any of the birds; two of the birds were successfully paired the next season and produced fledgelings.