BALB/c mice are often used in laboratory researches and its methodology needs to be standardized. A number of mice previously inoculated with Ehrlich's tumor were used under appropriate conditions to collect blood samples and analyze hematological parameters in automated and semi-automated equipment and allow this methodology to be made. The study successfully defined and established the methodology needed to obtain reference values for hematological parameters and to assist researchers develop their own methodology about animal handling and group management in experiments.