Anchovy fish meal with an approximate uniform moisture content of 10% was used for this study. Vapor adsorption isotherms were determined at 25 °C, 35 °C and 45 °C. The differential and integral thermodynamic properties were estimated using the Othmer method. The isosteric heat or differential enthalpy, as a function of moisture content, showed a maximum value around 4.5 g of water/100 g d. s. The heat of sorption increased gradually with an increase in sorbed water until reaching its maximum value near the monolayer, and at a given moisture content, decreasing with temperature. The molar entropy values obtained were high at low water contents and fell to a minimum near the monolayer value.