The cationic emulsifier oleamidopropyl dimethylamine has been responsible for many cases of cosmetic sensitisation in The Netherlands. Of 119 patients with proven cosmetic-related allergic contact dermatitis, 13 (11%) were allergic to oleamidopropyl dimethylamine. The clinical data of 12 patients, all sensitised by one particular baby body lotion containing 0.3% of the emulsifier, are presented. The cross-reaction pattern of oleamidopropyl dimethylamine was investigated by patch testing 13 patients allergic to the emulsifier with a series of related amideamine type emulsifiers. Most cross-reactions were observed to ricinoleamidopropyl dimethylamine lactate and tallowamidopropyl dimethylamine (11 patients, 85%). 9 patients (of 12 tested: 75%) reacted to lauramidopropyl dimethylamine and 6 (46%) to myristamidopropyl dimethylamine. It is concluded that the presence of oleamidopropyl dimethylamine in a concentration of 0.3% in stay-on cosmetics, especially when applied to damaged skin and/or the periorbital area, bears a definite risk of the induction and elicitation of contact allergic reactions.