Abstract. Let p be a prime number, X be an absolutely irreducible affine plane curve over Fp, and g, f ∈ Fp(x, y). We study the distribution of the values of the hybrid exponential sums Sn = Xon n ∈ I for some short interval I. We show that under some natural conditions the limiting distribution of the projections of the sum Sn, n ∈ I on any straight line through the origin is Gaussian as p tends to infinity.