A nerve net containing both acetylcholinesterase (AChE) and non‐specific cholinesterases (ChE) was demonstrated together with a corresponding adrenergic nerve net in the dilator region of the rat iris with a specially developed combination of the techniques for showing cholinesterases and adrenergic nerves. There is no such correspondence between adrenergic nerve fibres and AChE‐containing fibres of the iridic vessels, indicating a purely sympathetic innervation of them. Only AChE‐con taining fibres of the dilator region disappear appreciably upon chronic parasympathetic denervation. Chronic sympathetic denervation does not affect the cholinesterase‐staining properties. The presence of a nerve net in the dilator region, not degenerating upon sympathectomy and the purely sympathetic innervation of the iridic vessels was corroborated with methylene blue stainings. Thus, adrenergic (sympathetic) and AChE‐containing (mainly parasympathetic) fibres run closely together in the vegetative network of the dilator region, but the two types of fibres may also occur separately. It has as yet not been possible to identify the structure affected by the parasympathetic fibres in the dilator region.