Specific transcription factors participate in the decision making process that controls cell fate and differentiation. They function in the environment of chromatin and directly affect its structure and activity. This influence is especially apparent during the development regulation of gametes and in the course of the development of an early embryo. This review focuses on the role that Snf2h (Smarca 5) and Brg1 (Smarca 4), two factors belonging to the SWI/SNF2 family, play in the establishment of chromatin structure in germinal and early embryonic development.