Measurements of uniaxial strains introduced in Al 2 O 3 , MgO, AlMg 2 O 4 , AlN, Si 3 N 4 and SiC by light ion irradiation are compared to relative volume changes from neutron irradiation. The results are discussed in terms of a rate theoretical model of point defeat retention which includes spontaneous recombination. Strains from defect accumulation were derived with even higher precision from the bending of inhomogenously irradiated or implanted thin specimens. Stress distribution in this case is calculated by the finite element method and limitations of analytical stress calculations are given.