  We report resistivity measurements performed on KFe$_2$As$_2$ single crystals
down to $T$ = 0.3 K and in magnetic fields up to 17.5 T. The in-plane
resistivity vs. $T$ curve has a convex shape down to $\sim$50 K and shows a
$T^2$ dependence below $\sim$45 K. The ratio of the c-axis to in-plane
resistivities is $\sim$10 at room temperature and $\sim$40 at 4.2 K. The
superconducting upper critical field $B_{c2}(T)$ has been determined from the
resistivity data: $B_{c2}^{ab}$(0) = 4.47 T and $B_{c2}^{c}$(0) = 1.25 T. The
anisotropy parameter $\Gamma$ = $B_{c2}^{ab}$ / $B_{c2}^{c}$ increases with $T$
and is 6.8 at $T$ = $T_c$. The strong curvature of the $B_{c2}^{ab}(T)$ curve
indicates the existence of strong spin paramagnetic effects.
