Oxygen-related thermal donor formation in Czochralski silicon is characterized by the capacitance-voltage and deep level transient spectroscopy techniques as a function of 450°C anneal time following hydrogenation. Increases in the formation rate and number of thermal donor (TD) defects found after hydrogenation are reported. This study finds an increase in TD +/++ concentration in the near-surface region at short anneal times, but at longer times an elevated concentration was not observed. No acceleration through the sequence of thermal donor defects was detected. This fails to support the model of hydrogen lowering the barrier to oxygen diffusion and accelerating the TDn→TDn+1 transitions. This study does, however, support a model in which the hydrogen increases the available thermal donor core sites.