  Searches for the supersymmetric partners of top and bottom quarks using data
up to 340 pb$^{-1}$ taken at the Tevatron $p\bar{p}$ collider are described. We
report on searches for scalar top quarks $\tilde{t}$ in the decays
$\tilde{t}\to c \tilde{\chi}_1^0$ and $\tilde{t}\to bl\tilde{\nu}$ and for
scalar bottom quarks $\tilde{b}$ in the decay $\tilde{b}\to b
\tilde{\chi}_1^0$. No evidence for a signal has been found, but improved
exclusion regions have been derived in the framework of a generic minimal
superymmetric extension of the standard model.
