Reactions of the primary species of water radiolysis, viz. e(aq)(-), H atoms, and (OH)-O-. radicals, were studied with 3-hexyn-1-ol (3HX) and 5-hexyn-1-ol (5HX) using the pulse radiolysis technique. The rate constants for the reactions of e(aq)(-) with 3-hexyn-1-ol and 5-hexyn-1-ol were found to be 6.1 x 10(4) and 4.5 x 10(4) m(3) mol(-1) s(-1) respectively, whereas those for OH radical reactions with these compounds were 2.9 x 10(6) and 3.8 x 10(6) m(3) mol(-1) s(-1). The transient species formed in both cases were found to be good reductants. Oxide radical anion (O-.-) reacted with 3HX and 5HX with rate constants of 4.7 x 10(6) and 4.8 x 10(6) m(3) mol(-1) s(-1) respectively. The H atom reactions with hexyn-1-ols were found to give vinyl-type radicals which were reducing in nature. These radicals reacted with oxygen to give peroxyl radicals.