Introduction & Objective: Post dural puncture headache (PDPH) is a bothersome complication of spinal anesthesia specially in young parturient women after cesarean, which causes not only psychotic and somatic problems, but also increases hospital costs due to delay in patients discharge from hospital. The purpose of this study was to determine the effect of dexamethasone in improvement of complications of PDPH after spinal anesthesia in cesarean section. Materials & Methods: This is a randomised clinical trial in which 35 cases of parturient women, aged 21-44 years, who developed pain in head (PDPH), lumbar, shoulder, or more than one site due to spinal anesthesia after cesarean section in spite of consumption of NSAID drug, opoid, bed rest, rehydration. They received intravenously drip dexamethasone 0.2mg/kg (maximum 16mg) in one liter of normal saline for 2 hours. Visual analogue scale (0=no pain, 10=most unbearable pain) for patients before and after dexamethasone therapy was used and recorded. Results: The most common complaints of patients were headache (87.5%), low back pain (56.2%), shoulder and neck pain (25%). Results showed that mean of VAS pain score before tretment was 6.5±1.8 and decreased to 1.6±1.2 after treatment indicating a decrease of 77% in pain among the subjects. Conclusion: The advantage of dexamethasone therapy in comparisn with routine supportive therapy is the greater rapidity in pain relief and earlier release of patients from hospital.