The viability of white blood cells, spermatozoa of the epididymis, cells from minced spleen, lymph node and lung, and cells aspirated from the bone marrow of the sternum was studied using the vital dye exclusion test. The material comprised 123 medicolegal autopsy cadavers which had been stored in a mortuary cold room at +4 degrees C up to 10 days after death. Cells which excluded trypan blue were found in various specimens from all cadavers. However, there was marked individual variation in the results. The loss of viability of the white blood cells showed a moderate correlation (r = -0.78) with the increase in the post-mortem (p.m.) time, whereas the results for other tissues were not so significant. The K+ and Mg2+ and haemoglobin content and the osmotic resistance of the red cells correlated poorly with the p.m. time. The present results suggest that despite the general assumption that autolytic changes proceed rapidly at the cellular level, individual cells and especially blood cells may remain viable for a long time in cadavers kept at +4 degrees C.