Rate coefficients of Cl atom reactions with several ketones have been investigated at 298K and 1 atm using relative rate methods, monitoring substrates with both GC and FTIR and with two reference compounds. The following rate coefficients (1010 k/cm(3) molecule(-1) s(-1)) were obtained: k((2-pentanone)) (1.08 +/- 0.05), k((3-pentanone)) (0.89 +/- 0.12), k((3-methyl-2-butanone)) =(0.68 +/- 0.06), k((4-methyl-2-pentanone)) = (1.10 +/- 0.10), k((5-methyl-2-hexanone)) = (1.65 +/- 0.14), k((3-methyl-2-pentanone)) = (0.94 +/- 0.10) and k((3,3-chmethyl-2-butanone)) (0.48 +/- 0.05). The results are discussed in terms of Cl reactivity trends and existing literature. k((3-methyl-2-pentanone)) and k((3,3-chmethyl-2-butanone)) are poorly predicted with current structure activity relationships and revised parameters are proposed. In regions of high [Cl], these reactions can significantly reduce the fraction of ketones reaching the free troposphere. (C) 2015 Elsevier B.V. All rights reserved.