The relationship between perceived cognitive functioning and objective cognitive functioning was studied in 221 patients with multiple sclerosis. Perceptions of global cognitive functioning as well as perceptions of performance on specific cognitive tests were assessed. Patients' perceptions of global cognitive functioning in their daily lives were unrelated to their objective performance on the full cognitive test battery. However, patients' perceptions of their performance on specific tasks correlated with their objective performance on those tasks, even though they underestimated their performance on these tasks. The present study also evaluated predictors of patients' perceived cognitive functioning. Depression, anxiety, fatigue, and level of disability predicted perceptions of global cognitive functioning, whereas objective cognitive performance did not. These results add to our understanding of patients' expressed concerns regarding their cognitive functioning in the wake of multiple sclerosis, suggesting that such concerns should be interpreted with caution by clinicians.