Cytoglobin is a ubiquitously expressed hexacoordinate hemoglobin that may facilitate diffusion of oxygen through tissues. The protein,with calculated MW of 21 kd,runs as a 29kd one in canine retina,kidney,liver,lung,and heart. It may be caused by posttranslational modification of the protein. Various immuno-staining patterns were reported including nuclear,cytoplasm and extracellular location.