Euglycemic-hyperinsulinemic glucose clamp (EHGC) method is a gold standard for assessing insulin resistance in humans. However, this method has yet to be commonly used with dogs, due to the requirement of frequent blood sampling for glucose measurement and adjusting glucose infusion rate (GIR). The purpose of this study was to evaluate insulin resistance, induced either by Cushing Syndrome (CS) or diestrus in dogs, as determined by GIR by EHGC, using an artificial pancreas apparatus. Twenty animals were used in this study with ten (7 females and 3 males) serving as healthy controls, four (3 females, 1 male) diagnosed with CS, and six (all females) undergoing diestrus. A higher GIR value indicates increased insulin sensitivity and lower insulin resistance. GIR of healthy control animals was determined to be within a reference range of [10.6-21.3] with a median of 15.2 mg/kg/min. In comparison, the CS group had a median of 5.4 mg/kg/min; whereas the diestrus group exhibited a median of 8.9 mg/kg/min. Insulin resistant animals suffering from CS and undergoing diestrus demonstrated reductions of 65 and 40% in GIR, respectively; thus indicating differences in degree of insulin insensitivity can be discerned using the EHGC method.