Positron-lifetime (PL) and electrical resistivity studies of polycrystalline aluminium deformed by tensile stress at T 77 K were performed. It was found that the conventional trapping model (CTM) fails in interpretation of measured PL spectra due to strongly non-uniform spatial distribution of dislocations in the deformed samples. Therefore, a modified trapping model (MTM) was used in this study. Strongly non-uniform dislocation density was directly taken into account in the development of MTM. Comparison of the results obtained by MTM and CTM is given in the present work. Mean cell size in the deformed samples obtained from MTM analyses of PL spectra are compared with those measured by TEM. 440 J. C Ï i Âz Ïek et al. J. C Ï i Âz Ïek et al.