FTIR spectroscopic studies of the photolysis (lambda greater than or equal to 300 nm) of mixtures containing Cl-2 and C2H2, cis-CHCl=CHCl, or trans-CHCl=CHCl were carried out in 700 Torr of N-2 at 295 +/- 2 K. On the basis of the kinetic analysis of cis- and trans-CHCl=CHCl formed from C2H2, the branching ratio k(1a)/k(1b) has been determined to be 0.19 +/- 0.05. Cl + C2H2 (+M) --> cis-ClCH=CH(+M); Cl + C2H2 (+M) --> trans-ClCH=CH(+M). Implications of these results for our previously postulated mechanism of Cl atom initiated oxidation of C2H2 are discussed.