At present the therapeutical use of proangiogenic factors is in the focus of interest. Quantitation of angiogenesis, which is done particularly in animal models, is a prerequisite for the determination of the angiogenic effect of a particular substance. In the frame of this study a new method for quantitation of angiogenesis in vitro was established. Endothelial cells were incubated with angiogenic factors to be tested, and documented photographically in defined microscopical sectors over a certain time period. Subsequently defined stages of angiogenesis (1-8) were assigned. For each sector all stages assigned were summarized and compared with each other. This and additional morphometric studies showed that angiogenesis up to the development of lumenised capillary-like structures in vitro can be quantified. Validation of the method showed that routine and reproducible accomplishment should be possible for different investigators with a maintainable effort of time and costs.