The combination of tiletamine HCl and zolazepam HCl has been used on many species of wild mammals. Short induction time, low dosage, satisfactory safety margins, relatively constant immobilization time, and smooth recovery are benefits reported. This combination (Zoletil 100) was used during a study on behavioural ecology of the crested porcupine (Hystrix cristata) in a Mediterranean coastal area (Maremma Regional Park, Tuscany, Italy). We used this mixture 42 times on 31 individuals. Mean adult dose was (+/- SE) 7.24 +/- 0.37 mg/kg (74.0 +/- 3.0 mg/individual). Average adult induction time was 5.3 min (+/- 1.1) and average adult immobilization time was 22.6 min (+/- 6.0). One adult male porcupine died after chemical restraints. The use of tiletamine-zolazepam seems adequate for chemical immobilization of crested porcupines under field conditions, mainly because of its short induction time, small volume to be injected and wide safety margin.