The simultaneous uptake of gas-phase DMS-O-3 Mixtures by water as a function of temperature (274-300 K) was studied in a bubble train flow reactor. The uptake data yielded the second-order rate constant for the aqueous-phase reaction DMS + O-3 --> DMSO + O-2. The reaction products were established with NMR analysis. The reaction rate constant k(2) was measured at four temperatures: 274, 283, 293, and 300 K, yielding (5.1 +/- 2.0) x 10(8) M-1 s(-1), (5.9 +/- 2.0) x 10(8) M-1 s(-1), (8.6 +/-3.6) x 10(8) M-1 s(-1), and (11 +/- 4.5) x 10(8) M-1 s(-1) respectively. It is noteworthy that the magnitude of the aqueous reaction rate constant exceeds the corresponding gas-phase rate by a factor of about 10(6). The atmospheric importance of the aqueous-phase DMS/O-3 reaction is discussed.