We present the results of a search for third generation leptoquark (LQ) pairs in 110 +/- 8 pb^-1 of pbar p collisions at sqrt s = 1.8 TeV recorded by the Collider Detector at Fermilab. We assume third generation leptoquarks decay to a tau lepton and a b quark with branching ratio Beta. We observe one candidate event, consistent with standard model background expectations. We place upper limits on sigma(pbar p -> LQ \overbar LQ) - Beta ^2 as a function of the leptoquark mass M_LQ. We exclude at 95% confidence level scalar leptoquarks with M_LQ < 99 GeV/c^2, gauge vector leptoquarks with M_LQ < 225 GeV/c^2, and nongauge vector leptoquarks with M_LQ < 170 GeV/c^2 for Beta = 1.