For some 40 years, the development of the pituitary gland has been the subject of numerous studies. Several aspects of the origin, differentiation, and commitment of the pituitary cells, however, are still in doubt. The pituitary gland of several species apparently originates from the anterior ridge of the neural plate. Glandular pituitary cells can be committed very soon in embryonic life, as early as at the open neural stages. Numbers of differentiation and transcription factors may then control the expression of a given phenotype from the committed cells. Many questions remain unanswered about factors underlying such cellular commitment. These issues call for further studies to elucidate the molecular mechanisms of known and unknown factors controlling the embryology of the pituitary gland.