Rate constants of the reactions Cl + CH3OH -> CH2OH + HCl (k(1)) and Cl + CH3CHO -> CH3C(O) + HCl (k(3)) were measured at 100 Torr over the temperature range 230.3-297.1 K. Radical chemistry was initiated by pulsed laser photolysis of Cl-2 in mixtures of CH3OH and CH3CHO in a flow reactor. Heterodyne near-IR wavelength modulation spectroscopy was used to directly detect HO2 produced from the subsequent reaction of CH2OH with O-2 in real time to determine the rate of reaction of Cl with CH3OH. The rate of Cl + CH3CHO was measured relative to that of the Cl + CH3OH reaction. Secondary chemistry, including that of the adducts HO2 center dot CH3OH and HO2 center dot CH3CHO, was taken into account. The Arrhenius expressions were found to be k(1)(T) = 5.02(-1.5)(+1.8) X 10(-1)1 exp[(20 +/- 88)/T] cm(3) molecule(-1) s(-1) and k(3)(T) = 6.38(-2.0)(+2.4) X 10(-11) exp[(56 +/- 90)/T] cm(3) molecule(-1) s(-1) (2 sigma uncertainties). The average values of the rate constants over this temperature range were k(1) = (5.45 +/- 0.37) x 10(-11) cm(3) molecule(-1) s(-1) and k(3) = (8.00 +/- 1.27) X 10(-11) cm(3) molecule(-1) s(-1) (2 sigma uncertainties), consistent with current literature values.