In severely ill hospitalised patients with diabetes mellitus (type 1 and type 2) there is an increase in metabolic rate. Insulin requirements are increased and glycaemic control becomes more difficult to achieve. The insulin sliding-scale is a form of „top up‟ therapy used to supplement the patients existing hypoglycaemic medication. In 2002, research at Livingstone Hospital found that 14 different sliding scales were used in 38 patients (Du Plessis, 2002: 79). In 2006 the nurses and doctors working in the general medical wards at Livingstone Hospital indicated that they were willing to use a standardised insulin sliding scale protocol (Smith, 2006: 56). Thus the aim of this study was to assess whether a standardised insulin protocol can be effectively implemented. The objectives of the study were to: 1) assess insulin usage via insulin sliding scales prior to the implementation of the standardised insulin protocol; 2) implement the standardised insulin protocol; and 3) reassess insulin usage after the implementation of the standardised insulin protocol. As the study involved evaluating the use of insulin via the insulin sliding scale and the implemented insulin protocol, it occurred in four phases. The preliminary phase entailed obtaining ethical approval. The pre-intervention phase included data collection in the form of a nursing questionnaire and the auditing of patient medical records using a data collection tool. The intervention phase involved education sessions on the new insulin protocol for the nursing staff, and the implementation of a standardised insulin protocol, while the post-intervention phase comprised of post-intervention data collection, which included a nursing questionnaire, a prescribers questionnaire and the auditing of patient medical records using a data collection tool. The overall impression obtained from the comparison between the pre- and post-intervention nursing questionnaire was conflicting; in some aspects the educational intervention was successful in others not. Regardless the indication obtained was that the nursing staff require more in-service training on a more regular basis as a lack of knowledge regarding diabetes mellitus as a disease state may negatively affect patient outcomes. The overall response from the nursing staff towards the insulin protocol was positive. The prescribers‟ response to the insulin protocol was conflicted. The number of correct insulin sliding scale doses administered in the pre-intervention and post intervention phase improved by 5.25 percent. The number of incorrect insulin sliding scale doses administered during the pre- and post -intervention phase decreased by 5.25 percent. These results are positive and may be due to fewer sliding scales being prescribed in the post-intervention phase and the implemented insulin protocol. Only three (5.55%; n=54) inpatients with Type 1 diabetes mellitus were placed on the implemented protocol that is, the basal bolus regime, and rarely were dose adjustments to their insulin made rendering the effectives of the protocol undesirable. Only four (7.40%; n=54) inpatients with Type 2 diabetes mellitus were placed on the implemented protocol that is, an intermediate- to long-acting insulin (Protophane®). However all four patients experienced immediate improvements in their fasting blood glucose levels. These results indicated that by adding an intermediate- to long-acting insulin (Protophane®) to the therapy of a patient with Type 2 diabetes mellitus fasting blood glucose levels decrease. This would improve patient outcomes and decrease the risk of related diabetic complications. These limited results may indicate a clinical inertia on the part of the prescribers. Unfortunately overall the educational intervention was not successful and the implementation of the protocol was not successful and did not yield the desired results.