To compare the effectiveness of preload and coload for the prevention of Spinal Induced Hypotension (SIH) and vasopressor requirements.Randomized trial.Department of Anesthesia, The Aga Khan University Hospital, Karachi, Pakistan, from June 2007 - June 2010.Sixty patients were randomly divided into preload and coload group of 30 each. Patients with ASA1 - 3, aged 20 - 60 years were included. Patients with history of IHD, COPD, BMI > 30 and surgical procedure TURPwere excluded. All patients received crystalloid 10 ml/kg before induction of spinal anesthesia in preload group and at the time of spinal anesthesia in coload group. Blood pressure and heart rate were recorded at different time intervals till 45 minutes. Patients received ephedrine 5 mg when systolic blood pressure dropped below 90 mmHg and heart rate was less than 60 beats/minute and/or phenylephrine 50 micrograms when systolic blood pressure dropped below 90 mmHg and heart rate was more than 60 beats/minute.There was no statistically significant difference at different time intervals in heart rate, systolic and mean arterial pressure between the groups. Diastolic blood pressure was significantly different in both groups at 6 - 15 minutes after spinal anesthesia. SIH occurred (21) 70% and (15) 50% in preload and coload groups, respectively (p = 0.187). Ephedrine requirement for SIH was significantly high in preload group (p = 0.017). Phenylephrine requirement for SIH was high in preload group which was statistically non-significant (p = 0.285).Coload group has lower incidence of spinal induced hypotension and significantly less vasopressor requirement than the preload group.