The fermentation of the melon has been used to produce alcoholical beverages. In this process, the metabolism of the yeasts respiro-fermentative is influenced by nitrogen addition and correcting of the pH. The respiro-fermentative behavior of two yeast in presence of ammonium phosphate and adjusted pH were determined per stoichiometric of the sugars breathed and fermented. The addition of ammonium phosphate reduced the lag phase of baker's and CA-11 yeasts in the musts without pH adjustment. The highest rates of sugar fermentation were observed for baker's yeast with adjusted pH, while this same adjustment favored the respiratory metabolism in CA-11 yeast. The highest rates of sugar fermentation in musts with sole addition of ammonium phosphate were observed in CA-11 yeast. Therefore, the behavior respiro-fermentative of yeasts was different in presence of ammonium phosphate and pH adjustment during the fermentation of the melon.