Aims and Objectives: Aim of study is to evaluate effect of single epidural bolus of magnesium as an adjuvant to epidural fentanyl in patients undergoing an elective caesarean section. Method: Following approval of institutional grant committee,60 patients undergoing elective caesarean section were allocated into two groups of each thirty. Epidural block was performed in one group with 0.5%bupivacaine and fentanyl and other group with 0.5%bupivacaine, fentanyl and magnesium sulfate. All parameters will be observed and compared as onset and duration of analgesia. Results: Mean onset of sensory block in control group was 14.2min and magnesium group was 11.3min.Mean onset of motor block in control group was 13.4min and magnesium group was 13.6min.Mean duration of analgesia in control group was 247.27min and magnesium group was 319.57min.