Marking animals for identification is necessary in many aspects of wildlife research. In view of cost, practicality and ethical issues associated with many methods, we aimed to develop a suitable method for marking small wild vertebrates. We injected ultraviolet (UV) fluorescent tattoo ink subcutaneously into the tail of eight small mammal species and into the ventral area of seven lizard species. The method appeared suitable for seven mammal species and all seven lizard species, although survival after release remains to be determined. The method improved survival during handling of a sensitive rodent species compared with ear notching, which involved tighter head and chest control. Sixty-two recaptures indicated that the animals were healthy and the marks had not moved. UV-fluorescent tattoo ink is a cheap and ethical way of marking many small vertebrate species, although we recommend long-term evaluations of mark retention and the impact of tattoos on animals, including a potential increase in visibility to some predators. This marking method is likely to have applications for a wide range of wildlife.