A case of Adie''s syndrome in association with progressive sudomotor denervation has been presented. A similar case has been presented by Ross. It is suggested that the occurrence of these 2 conditions simultaneously in 2 patients may not be fortuitous. Decreased sweating was found predominantly on one side of the body but there was considerable irregularity in rate. In the regions of decreased sweating there was a diminished to absent wheal and flare response. These combined abnormalities suggest that perhaps the axon reflex could be important to both. Since sweating is a cholinergic function and Adie''s pupil is felt to be due to involvement of post-ganglionic cholinergic parasympathetic fibers, a defect may reside within postganglionic cholinergic sympathetic neurons or in the cholinergic mechanism itself. Against any involvement of the postganglionic neurons involved in sweating is the normal skin biopsy which discloses normal nerves and glands and the failure of previous investigations to demonstrate anatomically the elements of the axon reflex. This would favor a lesion involving the preganglionic neuron. It remains for other cases of Adie''s syndrome to be evaluated with respect to sudomotor activity.