A laboratory scale mechanical draft cooling tower with acrylic film type packing was studied.The performance of the tower was assessed at different mass flow ratios of water to airL/G, maintaining constant the water and air inlet temperatures and the packing material.It was found that the relation of the volumetric mass transfer coefficient kya versus the volumetric heat transfer coefficienth L ais not affected by the operating conditions.The small differences obtained are due to the experimental error.For all the value of the ratio L/G in the range of kya/h L a [3,25] the assumption of kya/h L a= cannot be considered and the relation has the following expression   0.34 624.76 y L k a h a  .However, for kya/h L a>25 the assumption of -m= is valid, and the value of kyais approximately 2800 Kg/h.m 3 .