Paramedian forehead flap is a workhorse for nasal reconstruction. However, vascular complications may lead to flap failure. The purpose of this study was to evaluate the blood flow objectively and determine the hemodynamic changes in paramedian forehead flap with respect to influential factors of age, gender, and smoking. Thirty patients who had paramedian forehead flap were followed up prospectively between 2010 and 2013. The blood flow was assessed by resistance index using Color Duplex-Doppler Ultrasonography. Resistance index was measured at the proximal and distal ends of each flap on the postoperative first day, first week, and second week. All data were analyzed using SPSS 15.0 for Windows. Fifteen patients were female and the mean of age was 60.9 years. Our results demonstrated statistically significant differences with gradual decreases in resistance to blood flow, when the resistance index values at the proximal and distal ends of paramedian forehead flap were compared (P < 0.001 and P < 0.001). Age, gender, and smoking did not have a negative impact on the resistance index values of paramedian forehead flap. To the best of our knowledge, this is the first study in which resistance in blood flow and hemodynamic changes of paramedian forehead flap were objectively determined using Color Duplex-Doppler Ultrasonography. The resistance index gradually decreases, although it is considerably high at the early postoperative interval. Age, gender, and smoking do not adversely influence the blood flow in a well-designed paramedian forehead flap.