  We present the discovery of ferromagnetism in single crystalline
Yb(Rh$_{0.73}$Co$_{0.27}$)$_{2}$Si$_{2}$ below $T_{C} = 1.30\,$K with a
spontaneous magnetic moment of $0.1\,\mu_{B}$/Yb along the crystallographic
c-axis. This is shown by the huge c-susceptibility peak, the hysteresis in
magnetization as well as by the field-dependent susceptibility and specific
heat data. This discovery motivates the reinvestigation of the magnetic order
in Yb(Rh$_{1-x}$Co$_{x}$)$_{2}$Si$_{2}$ with $x < 0.27$ and in pure
YbRh$_{2}$Si$_{2}$ under small pressures with field along the $c$-direction to
look for low-lying ferromagnetic order.
