We study the zero temperature conductance and magnetoconductance of ballistic textit{p-n} junctions in Weyl semimetals. Electron transport is mediated by Klein tunneling between textit{n}- and textit{p}- regions. The chiral anomaly that is realized in Weyl semimetals plays a crucial role in the magnetoconductance of the junction. With the exception of field orientations where the angle between $mathbf{B}$ and the junction plane is small, magnetoconductance is positive and linear in $B$ at both weak and strong magnetic fields. In contrast, magnetoconductance in conventional textit{p-n} junctions is always negative.