Some fibromyalgia (FM) patients engage in rumination (i.e. a chain of repetitive, passive and relatively uncontrollable thoughts focused on negative content) to cope with the pain and discomfort of daily activities. The partial model of rumination in chronic pain suggests that rumination processes may play a causal role in maintaining pain. Rumination might also be one of the key factors interfering with the reestablishment of adapted physical activity. The objective of this study was to test how rumination vs. distraction induction influence FM patients’ pain intensity, discomfort linked to pain, and affect after physical activity. Forty-seven participants with a diagnosis of FM were randomly assigned to undergo distraction induction vs. rumination induction after performing a physical activity in ecological setting. Their pain intensity, pain-related discomfort, and affect were measured at the baseline, after physical activity, and after rumination versus distraction induction. A series of mixed-design ANOVAs showed that rumination induction after physical activity impairs patients’ recovery in terms of pain intensity and discomfort, but not affect, as compared to the distraction condition. In conclusion, participants with fibromyalgia who engage in rumination following a physical activity recover less from their pain experience as compared to distraction induction. These results are consistent with the partial model of rumination in chronic pain and support the idea that rumination may play a causal role in the development and maintenance of pain.