While staying in an animal shelter, cats may suffer from chronic stress which impairs health and welfare. Offering hiding opportunities can significantly reduce behavioural stress in cats, but confirmation with physical parameters is needed. Therefore, the aim of this study was to determine the effect of a hiding box on behavioural stress levels (scored by means of the Cat-Stress-Score) and a physical parameter as body weight in newly arrived cats in a Dutch animal shelter during the first 12 days in quarantine situations. Twenty three cats between 1 and 10 years of age were randomly divided between the experimental (N = 12) and control group (N = 11) with and without hiding box. Stress levels were assessed on days 1, 2, 3, 5, 7, 9 and ...