Photoinitiators (PIs) are used as catalyzers for inks and lacquers that are cured with ultraviolet (UV) light, and they can contaminate foodstuffs by mass transference.The aim of the present paper is to study the migration of six photoinitiators (Irgacure 184, benzophenone, Irgacure 651, Irgacure 907, ITX, and EHA) into food simulants [distilled water, 3% acetic acid (w/v) in aqueous solution, 10, 20, 30, 60 and 95% ethanol (v/v) in aqueous solution]. Migration levels of the six PIs into different food simulants were compared after a 30 day contact period with the additivated plastic. A relationship between R (ratio between log K(o/w) and MW) and total migration was found for PIs with log K(o/w) < 5. Key parameters of migration processes were calculated according to a mathematical model based on Fick's second law. Diffusion (D) and partition coefficients were estimated and compared among different simulants, temperatures, and PIs to understand better the mechanisms of the migration process and the physicochemical properties that most influence this phenomenon. For instance, at 5 degrees C, in ethanol 95% (v/v), D ranged between 4.2 x 10(-11) cm/s for Irgacure 907 and 3.0 x 10(-9) cm/s for benzophenone.