Twenty-eight dogs were enrolled in the study to compare cortisol concentrations among healthy dogs, dogs with excess cortisol associated with pituitary dependent Cushing’s syndrome and dogs categorized as having “atypical” Cushing’s syndrome. The latter is diagnosed when dogs have clinical signs suggestive of excess cortisol (drinking a lot, infections, losing hair) but increases in peak cortisol concentration are not detected with routine tests. Nine hourly blood samples were collected from each dog through a catheter. The serum was saved and then sent to a lab for determination of cortisol concentrations. The cortisol concentrations from dogs within each group will be statistically compared to see if dogs with “atypical” Cushing’s syndrome have similar cortisol levels to those with pituitary dependent Cushing’s syndrome.