We present the results of a search for second generation leptoquarks S_2 using 19.3 pb^-1 of data collected at the Collider Detector at Fermilab (CDF) in ppbar collisions at sqrt s = 1.8 TeV during the 1992-93 collider run. We have searched for S_2 S-bar_2 pairs assuming that each leptoquark decays to a muon + quark with a branching ratio Beta. We find two candidate events, consistent with an expected background of 1.11 +/- 0.48. We obtain upper limits on sigma(ppbar -> S_2 S-bar_2) Beta^2 as a function of M_S_2. Using a Monte Carlo prediction for S_2 S-bar_2 pair production, we exclude M_S_2 < 131 GeV/c^2 for Beta = 1 and M_S_2 < 96 GeV/c^2 for Beta = 0.5 at 95% C.L.