We investigated the effects of various factors on blood rheology, which was evaluated by the passage time of heparinized whole blood using MC-FAN (Micro Channel array Flow ANalyzer). The time for 100 microliters of whole blood to pass through a microchannel array (Bloody 6-7) was determined. Each passage time was corrected by the saline passage time determined just before the measurement of sample blood. Our results suggest that blood rheology measured by MC-FAN is related to aging, body weight, body mass index and serum lipid parameters (total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglyceride). These results suggest that MC-FAN is useful to analyze blood rheology in pathophysiological conditions.