This work investigated the applicability in the food area of a new sorption equation recently developed by Ferro Fontán et al. (1982). The equation may be written, 1n (γ/aw) =α (m)-r, where, γ, α and r are parameters to be determined, m is the moisture content, and aw is water activity. It was found that the three parameter equation is able to describe the water sorption isotherm of 18 different foods in an extensive range of aw (up to about 0.95) with only 2–4% error (average) in the predicted moisture contents. Foods examined comprised, among other, oilseeds, starchy foods, and proteins.