Low energy electron attachment to propanoic acid (CH3CH2COOH) leads to a variety of negative fragment ions formed by dissociative electron attachment. The most intense reactions are operative at subexcitation energies (<3 eV) at cross-sections on the 10(-20) m(2) scale. They are due to dehydrogenation from the O site (direct cleavage of the O-H bond), but also more complicated reactions associated with hydrogen transfer and substantial geometric and electronic rearrangement. The present results demonstrate the potential of slow electrons to efficiently decompose organic acids. (C) 2004 Elsevier B.V. All rights reserved.