The use of laboratory techniques in veterinary practice is an indispensable tool which renders valuable information for the confirmation of a diagnosis. The blood analysis is one of most important routine analysis, since normal parameters can be a good indicator of good animal health. However, a normal blood analysis does not exclude the possibility that a bird is carrying entities such as psittacosis, virus diseases, or localized infections. The present review analyses the information related to the role of the clinical laboratory in bird hematology.