In this randomized controlled clinical trial patients with diabetes will be administered corrective doses of IV regular insulin or SC humalog for preoperative hyperglycemia to determine whether SC humalog results in improved intra and post-operative blood sugar control.The most common current practice at Emory University in the ambulatory surgical setting is IV administration of regular insulin for treatment of pre-operative hyperglycemia. Subjects will not be paid for their participation and will be assured of treatment for their hyperglycemia regardless of study participation.