Telemetry studies of newt species demand small transmitters. Two types of external attachments (sutured to epidermis and backpack) and traditional implanting in the peritoneal cavity were tested between groups of 5 adult individuals of the crested newt Triturus cristatus (mass 6-15 g) held in terrariums under controlled environmental conditions. The newts were anaesthetized with 1.5 g l–1 MS222, delivered in water and buffered to pH 6.9 by Na2CO2. Surgical plane of anaesthesia was achieved after 5-12 minutes and lasted for 30-60 minutes. External tagging proved unsuitable because transmitters became entangled in vegetation, and all animals shed their transmitters shortly after tagging, except for one that died. Transmitters that were surgically implanted in the peritoneal cavity were more successful. By the fourth day following surgery, the animals that had undergone surgery behaved similarly to control animals with respect to the use of cover. Two of the newts died, however, without showing any signs of illness in advance, and the cause of death could not be established. Based on the present experiments and published studies, implantable transmitters appear to be the best method for radiotagging small and medium sized urodele species such as T. cristatus, to gain crucial information on spatio-temporal terrestrial activity patterns, habitat utilization and hibernation sites. Additional research is needed to evaluate both short and long term effects on activity, behaviour and survival.