Research has suggested that individuals high in the trait tendency to ruminate have an increased risk for the development of psychopathology. Recent literature has begun to identify how rumination affects cognitive processes in order to document mechanisms of this risk. The current report evaluated the effects of both state and trait rumination on memory processes. Seventy undergraduates selected based on high and low levels of the trait tendency to ruminate completed the retrieval inhibition task. Prior to final recall, participants were randomly assigned to engage in either a rumination or distraction task. Results found that state rumination impaired retrieval-induced forgetting, and trait rumination impaired forgetting of no longer relevant stimuli. Additional analyses suggested that self-report of shifting ability was associated with reduced inhibiting of irrelevant stimuli. These findings highlight the importance of evaluating both state and trait rumination when evaluating the effects of repetitive negative thinking on cognitive processes.