During tracking studies, the behaviour of animals may be affected by the tracking and tagging methods used, which may influence the results obtained. Our aim was to assess the impact of transmitter mass and the duration of tracking period on the body mass change (BMC) of two anuran species that were fitted with externally attached radio transmitters. Bufo b. spinosus and B. viridis were radio-tracked for three months during summer in the active tract of a large gravel-bed river (Tagliamento River, NE Italy). Our results demonstrated that transmitter mass and the duration of the tracking period did not affect BMC of the two anurans in their terrestrial summer habitats because methodological factors poorly predicted variation in BMC. Therefore, we encourage the use of tracking methods in amphibian ecology.