We investigate the rare decay Λb→Λγ which receives
both short and long distance contributions. We estimate the long distance
contributions and find them very small. The form factors are obtained
from Λc→Λℓˉνℓ using heavy quark symmetry
and a pole model. The short distance piece opens a window to new physics
and we discuss the sensitivity of Λb→Λγ
to such effects.