The heats of formation of GeH4, GeF4, and Ge(CH3)4 are computed at CCSD(T) level of theory at the complete basis set limit. Relativistic effects, core valence correlation, spin orbit effect, and zero point energy are explicitly calculated in this study. Relativistic recoveries for these molecules are investigated with different size of correlation space. An unusually large relativistic effect is observed in GeF4. Our best calculated geometries for GeH4 and GeF4 are in excellent agreement with the high precision experiments. Anharmonic correction to the zero point energy is significant for Ge(CH3)4. Our best calculated values for the 298 K heats of formation of GeH4, GeF4, and Ge(CH3)4 are 82, -1194, and -123 kJ/mol, respectively. © 2005 Elsevier B.V. All rights reserved.