Shivering is a common and annoying side effect of spinal anesthesia. Recently, antishivering drugs, including clonidine and granisetron have been introduced as potential treatments. Aim To compare the effectiveness of intravenous clonidine and granisetron in preventing shivering that occurs after spinal anesthesia for cesarean section (CS). Patients and method One hundred eighty-six parturients scheduled for CS were allocated randomly into three groups,62patientseachtoreceiveintravenousclonidine0.5μg/kg(groupCl), 1mg granisetron (group G) or 10ml normal saline (groupC), 20min before spinal anesthesia. CS was started when the sensory level reached T6 and the bromage scale was 3. The primary outcome was the incidence of shivering, while secondary outcomes included maternal core body temperature, vital signs and satisfaction, neonatal outcomes, and maternal and neonatal adverse effects