The aim of this study was to investigate the sensitizing potential of 12di(meth)acrylates, when tested in the Guinea Pig Maximization Test (GPMT) and Freund's Complete Adjuvant Test (FCAT). In these tests the same (molar) concentration was used for intradermal induction. The results (see table, below) show that dimethacrylates are moderate to strong sensitizers in the guinea pig. In the group of diacrylates, no sensitization to diethylene glycol diacrylate was observed. 1,2‐ethanediol diacrylate and 1,6‐hexanediol diacrylate sensitized a number of animals. The challenge reaction pattern of the FCAT with 1,4‐butanediol diacrylate, neopentane diol diacrylate and 1,5‐pentanediol diacrylate differed from that commonly observed with sensitizers. Positive reactions were seen only to the maximum non‐irritant concentration at 24 h in the challenge at day 21. At 48 h and in the second challenge at day 35, the reactivity had decreased or disappeared. This different reaction pattern makes it difficult to classify these monomers with certainty as sensitizers.In most of the FCATs, a decrease in reactivity in successive challenges was found. Possible explanations for this decrease and for the different challenge reaction patterns of some diacrylates are discussed.The skin irritant capacity of di(meth)acrylates was estimated after one open application. Diacrylates are very strong irritants on guinea pig skin. Dimethacrylates are weak