Quality of the transfused blood units are needed to be controlled, because severe storage lesion leads to clinical adverse effects on critically ill patients. Currently, visual assessment of hemolysis is used to control the quality of the blood units by inspecting the pink discoloration in blood bag. However, the color of blood units can be uniquely and more accurately defined by a set of tristimulus values or color coordinates in a color space. The objective of the study is to monitor daily changes in the color parameters of stored blood and relate them with the changes in hemolysis index. Red blood cell (RBC) suspensions collected from 7 male volunteers were used for the study. On each day of storage, 24 colorimetric parameters in various color spaces were measured. Besides, each week of storage, standard hemolysis measurements were performed by taking blood samples from blood bags. Colorimetric parameters: tristimulus X, u', u-v saturation, Hunter a, CIE a*, CIELAB chroma and the correlated color temperature (CCT) that mostly correspond to red contents of the color stimuli changed significantly (p<0.05) for each sample after the third week of storage. Except CCT, hemolysis showed good correlation (r>0.65) (p<0.005) with those parameters. However u', u-v saturation and CIE a* are not sensitive enough to detect hemolysis in the first two weeks of the storage.