We report results from a study of the charmed double strange baryons Ωc 0 and Ωc * 0 at Belle. The Ωc 0 is reconstructed using the Ωc 0 → Ω- π+ decay mode, and its mass is measured to be (2693.6 ± 0.3-1.5 +1.8)   MeV / c2. The Ωc * 0 baryon is reconstructed in the Ωc 0 γ mode. The mass difference MΩc* 0 - MΩc0 is measured to be (70.7 ± 0.9-0.9 +0.1)   MeV / c2. The analysis is performed using 673 fb-1 of data on and near the Υ{hooked} (4 S) collected with the Belle detector at the KEKB asymmetric-energy e+ e- collider. © 2008 Elsevier B.V. All rights reserved.