Summary—Rapid developments in computer technology combined with new fluorescent dyes and monoclonal antibody production have led to the development of a powerful tool: flow cytometry. The techniques of flow cytometry can be applied in a wide clinical field, from routine tasks to research in immunology and hematology. The availability of automated instruments and standardized sample preparation methods have led to its daily clinical use, helping diagnosis, prognosis or monitoring therapy. Further advances will be made with the introduction of multi‐parametric analysisiequantification of antigen expression of cell surface antig