Aim: To determine the role of CT perfusion in patients with acute ischemic stroke in the patients of less than 12 hrs of acute stroke symptoms. Materials and Methods: The present study is a prospective study to determine the value of CT in evaluation of cerebral perfusion by use of a bolus of iodinated contrast medium in 30 patients with acute stroke, carried out in Department of Radiodiagnosis, Kamineni Hospitals, L.B. Nagar, Hyderabad. All the patients enrolled in study were evaluating in period of 12 months. After obtaining the informed consent the patient’s personal identification information was recorded. The signs and symptoms of acute stroke less than 12 hours duration with any other systemic illness at the time of presentation were noted. Ingenuity 128 slice CT Machine, Phillips. Perfusion CT software - Ingenuity 128 slice CT scanner, Phillips Iohexol Contrast media were used. Results: Mean age of subjects was 60.8 ± 13.22 yrs. Majority of subjects in the study i.e., 60% were males and 40% were females. 46.7% of lesions were on Right side, 36.7% of them on Left side, 13.3% on Midline and 3.3% on both cerebral hemispheres. Majority of subjects (93.3%) presented with Weakness as symptom. Non contrast CT showed that 40% had Loss of Gray Matter Interface. On CT perfusion 10% had ACA involvement, 33.3% had LCS of MCA involvement. PS value has significant co-relation with hemorrhagic transformation. There was significant association between PS Core infarct and Hemorrhagic transformation. It was observed that there was significant association between Infarct volume and Predicted Modified Rankin Score. There was no significant association between Actual score and Haemorrhagic transformation. Conclusion: PS elevation more than 5ml/min/100gm appears to be a promising marker for predicting the risk of HT in acute stroke patients. More importantly, a small PCT lesion (<100 mL) identifies patients who will have a small final infarct and good clinical outcome. A large PCT lesion (>100ml) identifies patients who will have a large final infarct and poor clinical outcome. PCT can play an important role in guiding acute stroke treatment.