We investigated the incidence of timing problems with insulin-related processes in a subacute inpatient unit in Melbourne and found that nursing staff often conduct blood glucose level (BGL) testing longer than 30 minutes before insulin administration (between 22% and 41%). Nurses are better at administering rapid-acting insulin doses within the recommended time before food intake (94%) than conventional insulin analogue doses (43%). BGL testing is carried out too early due to established ward practices and busy mornings, as well as poor guidance from an outdated policy. The timing of conventional insulin analogue administration is by nature more complex than that of rapid-acting analogues. Current timing places inpatients at risk of harm from hypoglycaemia. The high level of care demand in our subacute unit contributed to timing problems, and this is likely to be a problem in other units. Process redesign, policy revision and staff education could be used to reduce the risk of hypoglycaemia in this subacute inpatient unit.