A mixture of tiletamine and zolazepam (Zoletil) was used to immobilize 29 captive born Iberian wolves. Based on their excitability during handling procedures the animals were categorized as excited (n = 15) and unexcited (n = 14). We observed differences in the responses of these groups to the drugs. Although immobilized with higher doses (mean +/- SD of 6.94 +/- 2.13 versus 5.04 +/- 1.74 mg/kg for the unexcited) the excited individuals had an irregular and less predictable response, with five individuals needing additional dosages in the excited group compared to one animal in the unexcited group. Arousal time and duration of immobilization of excited wolves was not correlated to initial drug doses, but was in unexcited animals; the excited group had a poorer thermal regulation. Differences in arousal time and duration could be the a result of the different doses used. Excited wolves were older than unexcited (5.4 +/- 3.07 versus 2.86 +/- 2.11 years, respectively). For captive wolves, doses of about 5 mg/kg are recommended for non-excited and 10 mg/kg for excited individuals.