We search for the rare decay W^+/- -> D^+/-_s gamma in 82 pb^-1 of
ppbar collisions recorded with the Collider Detector at Fermilab.  At the 95%
confidence level, we find an upper limit on the relativ branching fraction to
be Gamma(W^+/- -> D^+/-_s gamma)/Gamma(W^+/- -> e^+/- nu)<1.2 x 10^-2.