In CAF-electrophoresis, extracts of cardiac muscle and of kidney tissue, after storage at 4 degrees C, show a roughly linear increase of the equivalent to the Albumin fraction. This increase depends on the time elapsed and is explained by the relatively high stability of this fraction compared to organ proteins, which appear in the globulin region. Thus, a sort of internal standard exists and can be used as a parameter for the determination of the post mortem period. Hepatic tissue is less suitable for this kind of investigations as the relation of the post mortem period and the values of the relative concentration of the fraction do not show the linearity found in cardiac muscle and kidney tissue. Splenic tissue shows no distinct trend and the findings are of little value. The present investigations were arranged in such a way that taking the order of magnitude for the equivalent of the Albumin fraction as a guideline led to a determination of the maximum post mortem period, i.e., the maximum period of time the body lay after the hour of death. The tables of this paper show the figures for the individual organs.