Phenylcyclohexylglycoloylester of hydroxyethyldimethylhydrazonium (compound VGFB-3113) has been shown earlier to have a strong antimuscarinic effect on smooth muscle. Its affinity to muscarinic binding sites in homogenates of rat heart ventricles (M2 subtype), submandibular salivary gland (M3 subtype) and brain cortex (predominantly Ml subtype) has now been investigated in radioligand displacement experiments using (3H)quinuclidinyl benzilate ((3H)QNB) as a relatively non-specific muscarinic ligand. VGFB-3113 inhibited the binding of (3H)QNB with pKj values of 8.17, 8.73, and 8.52 in the heart, salivary gland, and brain cortex, respectively. It is concluded that the compound has a high affinity for muscarinic binding sites without strong preference for any of the Ml-M3 subtypes.