Let Ω be a convex set in Rd which contains 0 in its interior and let N(t) be the number of points with integer coordinates in the dilate tΩ. N(t) is asymptotic to td|Ω| as t→∞ and we discuss estimates for the error term E(t)=N(t)−td|Ω|. In particular we report on sharp bounds for mean square discrepancies (joint work with A. Iosevich and E. Sawyer).