Background: Hypotension is one of the common complications in patients undergoing surgeries under spinal anesthesia. This phenomenon is comparatively more in pregnant women undergoing caesarean section under spinal anesthesia due to anatomical variations in the spinal cord and physiological changes in pregnant women. Maternal position may influence the spread of the local anaesthetic drug. So, in this study we have aimed to compare incidence of hypotension and various other parameters like onset of sensory and motor blockade, total number of mephentermine incremental doses (5mg/dose) required in each group to correct hypotension after induction of spinal anesthesia in sitting and lateral position for caesarean sections. Methods: Seventy American Society of Anesthesiologists physical status I and II patients undergoing elective caesarean section were randomnly divided into two groups by closed envelope technique to receive spinal anaesthesia in the lateral position (Group L) or the sitting position (Group S). In Lumbar (L3­ 4) interspace, lumbar puncture was done after taking aseptic precautions, plain bupivacaine 0.5% heavy 10 or 12 mg according to the height was injected after confirming free flow of cerebrospinal fluid. After this, they were placed in the supine position immediately with right wedge providing for left lateral uterine displacement to avoid supine hypotension syndrome. Maternal blood pressure was measured every minute for 5 minutes, every two min for 10 min and 5­ minutely thereafter. Hypotension was defined as a fall in systolic blood pressure >20% of the baseline value or a value <90 mmHg. Results: Statistical studies showed that number of patients who received spinal anesthesia in lateral position had significantly more incidences of hypotension (19 incidences) compared to those who received in sitting position ( 10 incidences) with P value being (P= 0.048). And also there was faster onset (average time) of action (sensory and motor) in Group L (5 minutes for sensory and 6.2 minutes for motor) than compared to Group S ( 7 minutes for sensory and 7.4 minutes for motor) but not statistically significant ( P= 0.361 for sensory and 0.639 for motor). We also observed that, total number of incremental doses (5mg/dose) of mephentermine used were more in patients who received spinal anaesthesia in lateral position (n= 10 increments) than compared to those who received in sitting position( n=5 increments) but it was not statistically significant (P=0.145). Conclusion: Spinal anesthesia given in lateral position of the patients for caesarean section causes significantly more incidences of hypotension than that given in sitting position. And there were no significant differences with respect to onset of sensory and motor block and mephentermine requirement between the groups.