This paper focuses on the radiation-damage effects when applying the same total X-ray dose to protein crystals at different dose rates. These experiments have been performed on both a selenomethionated protein and on bovine trypsin using dose rates that span nearly two orders of magnitude. The results show no clear dose-rate effect on the global indicators of radiation damage, but a small measurable dose-rate effect could be found when studying specific radiation damage. It is hypothesized that this observed dose-rate effect relates to differences in the steady-state free-radical concentration.