Controversies concerning clinical management practices have prevailed from time immemorial. The management of glycemic status is one such management arm. This requires a physiological range to be individually defined and targeted for each patient during each phase of the critical illness. Ongoing research continues attempts to gain knowledge in this aspect to provide the best possible management guidelines, especially for the neurocritically ill. Despite the ongoing extensive research in these areas to provide the best possible practice guidelines, ambiguity still needs to be addressed concerning the intensity of treatment, target thresholds, and duration of therapies. A “personalized” approach to glycemic control in the critically ill, with recognition of preadmission glycemia, is supported by an emerging literature. This chapter will review the different sources of evidence available in the literature concerning this critical intervention. We suggest the best practices for this commonly faced controversy and elaborate on what needs to be researched further.