Seventy-four healthy mixed-breed dogs were studied collecting behavioural data by means of 'focal animal sampling' and 'all occurrences' methods; the ethogram utilised consisted of more than 100 behavioural patterns. All dogs were taken outside the shelter for a walk to analyse their reaction to a novel environment. In addition, three faecal samples were collected from each dog on three consecutive days during daily routine, to measure the levels of cortisol metabolites (CM) to evaluate adrenocortical activity. A Principal Component Analysis (PCA) identified five primary factors: 'subordination/aggressiveness', 'intraspecific dominance-activity', 'anxiety-sociability towards dogs', 'playfulness' and 'sociability towards humans'. Dogs that showed a confident-independent temperament in a familiar context (within the shelter), showed fear in novel situations (outside the shelter). Despite the absence of a proper control we hypothesise that the stress levels were low both behaviourally and physiologically: neither stereotypies nor inactivity and lack of interest in the surrounding environment was observed, and the median CM concentration was moderately low. Lower concentrations of faecal CM were recorded in dogs with a temperament 'sociable to human beings' which were also associated with a longer stay in the shelter.