The aim of this study was to use behavioural observations to assess the welfare of the red-necked pond turtles (Mauremys nigricans) kept in a zoo. In 2000, red-necked pond turtles were put on the critically endangered list. Today, the species appears to be extinct in the wild. The welfare of captive populations of the species will have an important impact on their survival. Due to unusual aspects of reptile biology and a lack of monitoring standards, the main criteria available for welfare assessment for these animals may be behavioural. Based on the results of this study, it can be inferred that the welfare of the observed turtles has been moderately well-preserved; however, the artificial conditions created by humans are not able to fully satisfy the behavioural needs of the studied animals