To examine whether symptom exaggeration is a factor in complaints of cognitive dysfunction using 2 new validated instruments in patients with fibromyalgia (FM). Ninety-six patients with FM and 16 patients with rheumatoid arthritis (RA) were administered 2 effort or symptom validity tests designed to detect exaggerated memory complaints as part of a battery of psychological tests and self-report questionnaires. A large percentage of patients with FM who were on or seeking disability benefits failed the effort tests. Only 2 patients with FM who were working and/or not claiming disability benefits and no patient with RA scored below the cutoffs for exaggeration of memory difficulties. This study illustrates the importance of assessing for exaggeration of cognitive symptoms and biased responding in patients with FM presenting for disability related evaluations.