Cold silicon and germanium clusters have been produced in a supersonic molecular beam by laser vaporization of a silicon or germanium rod. The cluster beam is characterized by laser ionization studies and time of flight mass analysis. Both large Si and Ge clusters are found to have similar fragmentation patterns. They fisson into stable subunits rather than lose atoms sequentially. Two-color stepwise ionization experiments reveal that large Si and Ge clusters have an intermediate state with a lifetime of approximately 1 ns, thereby establishing the feasibility of resonant two photon ionization (R2PI) spectroscopy on these clusters.