Stereotypic behaviours, i.e. repetitive, unvarying and apparently functionless behaviour patterns, are intriguing as they occur in a variety of domestic /captive species without any clear adaptive function. Among different hypotheses, the coping hypothesis predicts that stereotypic behaviours are a way for animals in unfavourable environmental conditions to adapt. As such, they are expected to have a lower physiological stress level (i.e. glucocorticoids) than non-stereotypic animals. However, attempts to link stereotypic behaviours with glucocorticoids have yielded contradictory results. Here we investigated correlates of stereotypic behaviours and glucocorticoid levels in two large samples of domestic horses (NStudy1=55, 41 geldings, 14 mares, 5-20-year old; NStudy2=58 mares, 4-20 year old), all kept for four months (study 2) to at least one year (study 1) in various sub-optimal conditions (e.g. confinement, social isolation...) and already known to experience altered welfare states. Each horse was observed in its stall using focal sampling (study 1, 30 minutes in total per horse) and instantaneous scan sampling (study 2, 92 scans per horse). Plasma (collected in study 1; two times per horse between 18:00 and 19:00 over 2 consecutive days) and faecal samples (collected in both studies) were collected to assess cortisol levels. Faecal samples were collected between 12:00 and 13:00 three times per horse on three different days in study 1, once between 08:00 and 10:00 in study 2. Results showed that neither plasma cortisol nor faecal cortisol metabolites concentrations differed between stereotypic and non-stereotypic horses (Mann Whitney tests, p>0.05), nor did they correlate significantly with frequencies of stereotypic behaviours or time spent performing stereotypic behaviours (Spearman correlations tests, p>0.05). As non-invasive measures were performed in both studies, bias due to human interventions during sampling has been minimized. Cortisol measures therefore do not indicate that stereotypic horses cope better, at least in term of basal adrenocortical activity.