The endangered Pygmy Blue Tongue Lizard, Tiliqua adelaidensis, occupies narrow vertical burrows, probably constructed by spiders. We assessed the fitness of female lizards in artificial burrows added to a 1-ha plot within a natural population, over a three-year period. Compared with females in natural burrows, females in artificial burrows had significantly better body condition and produced larger offspring with better body condition. We discuss possible explanations for these differences but conclude that adding artificial burrows was not detrimental to reproductive females in a population and could be used in the conservation management of this species.