  We study the possibility of improving the constraints on the lifetime of
gravitino dark matter in scenarios with bilinear R-parity violation by
estimating the amount of cosmic-ray antideuterons that can be produced in
gravitino decays. Taking into account all different sources of theoretical
uncertainties, we find that the margin of improvement beyond the limits already
set by cosmic-ray antiproton data are quite narrow and unachievable for the
next generation of experiments. However, we also identify more promising energy
ranges for future experiments.
