Rate constants for the reactions of OH radicals with four C-6-C-10 cycloalkenes have been measured at 297 +/- 2 I( using a relative rate technique. The rate constants (in units of 10(-11) cm(3) molecule(-1) s(-1)) were cyclohexene, 6.35 +/- 0.12; cis-cyclooctene, 5.16 +/- 0.15; cis-cyclodecene, 4.18 +/- 0.06; and 1-methyl-1-cyclohexene, 9.81 +/- 0.18, where the indicated errors are two least-squares standard deviations and do not include uncertainties in the rate constant for the reference compound 1,3,5-trimethylbenzene. In addition, a rate constant of (4.8 +/- 1.3) x 10(-11) cm(3) molecule(-1) s(-1) was derived for the reaction of OH radicals with 1,6-hexanedial, relative to our measured rate constant for OH + cyclohexene. Analyses of products of the OH + cyclohexene, 1-methyl-1-cyclohexene, and cis-cyclooctene reactions by direct air sampling atmospheric pressure ionization mass spectrometry and/or by combined gas chromatography mass spectrometry showed the presence of products attributed to cyclic 1,2-hydroxynitrates and the dicarbonyls 1,6-hexanedial, 6-oxo-heptanal, and 1,8-octanedial, respectively. These dicarbonyl products, which are those formed after decomposition of the intermediate cyclic 1,2-hydroxyalkoxy radicals, were quantified as their dioximes, with molar formation yields of 76 +/- 10%, 82 +/- 12%, and 84 +/- 18% from the cyclohexene, 1-methyl-1-cyclohexene, and cis-cyclooctene reactions, respectively. Combined with literature data concerning 1,2-hydroxynitrate formation from OH + alkenes and the estimated fractions of the overall reactions proceeding by H-atom abstraction, 90 +/- 12%, 95 +/- 13% and 108 +/- 20% of the products or reaction pathways from the OH radical-initiated reactions of cyclohexene, 1-methyl-1-cyclohexene, and cis-cyclooctene in the presence of NO are accounted for.