In two severe but nonfatal cases of poisoning from dermally absorbed parathion, initial dilatation of the pupils resulted in delay in accurate diagnosis and adequate treatment, especially full atropinization. Overemphasis was accorded miosis. There is need for reliance on a carefully taken history of exposure and on a comprehensive analysis of all signs and symptoms. The presence or absence of miosis is of practical but limited significance in the differential diagnosis of early parathion poisoning.