In a double blind controlled, randomized clinical trial study, we have investigated the efficacy of I.M ephedrine in 100 patients undergoing surgery under spinal anaesthesia to level T6. Fifty patients' received ephedrine 0.5mg kg −1 (2cc) in deltoid muscle of right arm just before spinal anaesthesia. Fifty patients' received equal volume of distilled water (2cc). Patients in both groups were given the same volumes of N/S (10CC. kg −1). Mean arterial pressure during the first 60 min after anaesthesia remained significantly more stable in the ephedrine group (P= 0.000002) and the incidence of hypotension lower than base MAP was very lower than placebo group (2% versus 40% and P=0.000009). We concluded that 0.5 mg. kg −1 ephedrine I.M just before spinal anaesthesia is a simple and effective means of reducing the incidence of hypotension episode after spinal anaesthesia.