The moisture migration and drying properties of hardened cement paste and mortar are studied experimentally and analytically. Thin-wall cylindrical specimens with a thickness of about 1.0 mm are used to reduce hygral gradients. The specimens are loaded with different compressive stresses in the range 0-11 MPa. Two test series are performed: loss of water (test 1) and migration of moisture through the thin wall of the specimens (test 2) are measured. Furthermore, the experimental results are analyzed as a non-linear diffusion process, by means of the finite element method. The effects of the compressive stress and aggregates are discussed, referring to the diffusion coefficients obtained.