Hypocalcaemia after total or completion thyroidectomy has traditionally required 48 hours or longer inpatient monitoring of serum calcium levels. The use of parathyroid hormone (PTH) levels to predict postoperative hypocalcaemia is well established. This study aimed to measure the impact of a management plan based on postoperative PTH on achieving safe early discharge after thyroidectomy. A prospective cohort study of 76 patients undergoing total or completion thyroidectomy was performed. Serum PTH level was measured 4-12 hours postoperatively and used to stratify patients into three groups: normal PTH (> 12 pg/mL), undetectable PTH (< 3 pg/mL) and intermediate PTH (4-11 pg/mL). A subgroup analysis was performed on a cohort of patients after a change in the management philosophy aiming for day 1 discharge based on the postoperative PTH. Seventy-five percent of eligible patients were successfully discharged on day 1 with no complications or readmissions; 21% of patients had intermediate or undetectable PTH levels and were monitored for 48 hours. No patient required intravenous calcium and no patient suffered permanent hypoparathyroidism. A single PTH measurement at 4-12 hours postoperatively allows for accurate prediction of patients at risk of hypocalcaemia. Patients with a normal postoperative PTH level can be safely discharged on the first postoperative day.