Every year sees an increase in the number of dogs admitted to rescue shelters. However well these dogs are cared for in the shelter it cannot be ignored that being in such a situation is stressful, and the time spent in the shelter may change the dogs’ behaviour which may in turn influence their chances of being bought from the shelter. This research examined the behaviour of stray and unwanted dogs on their first, third and fifth days in an Ulster Society for the Prevention of Cruelty to Animals (USPCA) shelter. A questionnaire was also distributed to members of the public to determine how popular the USPCA was as a place from where to purchase a dog, and what factors about a dog's physical characteristics, behaviour and environment influenced potential buyers. Results revealed no significant difference between the behaviour of stray and unwanted dogs although the public viewed stray dogs as much less desirable than unwanted dogs. Time in the shelter had no adverse effects on the dogs’ behaviour. Indeed those changes which did occur during captivity, dogs being more relaxed in the presence of people and eating food more quickly, may be considered as positive changes. The USPCA was viewed as a popular place from which to buy a dog. Of factors influencing the public's choice, the dog's environment and behaviour appeared more important than its physical characteristics. The presence of a toy in the dog's cage greatly increased the public's preference for the dog, although the toy was ignored by the dog. The welfare implications of sheltering dogs are discussed.