Many homeodomain transcription factors having a distinct temporal and spatial expression pattern have been described in the developing anterior pituitary gland. By interacting with each other, as well as with other extrinsic and intrinsic signals, they control cell determination, cell differentiation and eventually maintenance of cell function which is most important for the life long secretion of the pituitary derived hormones in an appropriate manner. The different phenotypes, as mainly studied in the mouse, may help to analyse the consequences of disruption of a known or yet unknown individual transcription factor in humans. Therefore, to study the different steps in morphogenesis will shed light onto developmental processes which will open a most fascinating time not only for basic scientists, biologist but also for clinicians.