One of the main problems of the insulin hypoglycemia test (IHT) is the failure to achieve an adequate hypoglycemia (blood glucose, <45 mg/dl) with the standard dose of insulin used. The aim of the study was to identify by means of homeostasis model assessment (HOMA) the subjects at risk for hypoglycemia failure during IHT. For this purpose 32 patients in whom an IHT was performed were prospectively included. Receiver operating characteristics curve analyses were performed to assess the sensitivity and specificity of both insulinemia and HOMA. Eight patients (25%) did not reach adequate hypoglycemia. A serum insulin concentration above 17.7 μIU/ml or a HOMA value above 4.38 identified those subjects who would not reach adequate hypoglycemia with a probability of 75%. By contrast, when the levels of either insulinemia or HOMA were lower than the cut-off points mentioned above, the probability that individuals would reach sufficient hypoglycemia was 89.5%. In conclusion, quantitative estimate of insulin resistance by HOMA is a simple and reliable method that permits identification of individuals at risk of not reaching adequate hypoglycemia during IHT. In these patients, either alternative tests or a higher dose of insulin should be considered.