We have studied the photolysis of butenedial at 193, 248, 280, 308, 351, 400, and 450 nm by using laser photolysis combined with cavity ring-down spectroscopy. The HCO radical is a photodissociation product at 193 and 248 nm. The corresponding HCO quantum yields are 0.55 +/-0.07 and 0.12 +/- 0.01, independent of butenedial pressure and nitrogen buffer gas pressure. Absorption cross-sections of butenedial are (6.88 +/- 0.39) x 10(-18) and (3.62 +/- 0.69) x 10(-19) cm(2) at 193 and 248 nm. The end-products from the photolysis of butenedial at 193, 248, 308, and 351 nm were measured by FTIR. Acrolein and 3H-furan-2-one were observed and their yields have been estimated. (c) 2005 Elsevier B.V. All rights reserved.