Objectives The aims of this study were to investigate the presence of cognitive impairment in fibromyalgia syndrome [FMS] patients using the clock drawing test [CDT] and evaluate its correlation with age, educational level, pain, fatigue, functioning, depression, anxiety, and sleep disturbance.Methods Sixty- three patients with FMS and 62 healthy normal controls [HNCs] were enrolled in thise study. Visual Analog Scale [VAS] pain, VAS fatigue, VAS sleep disturbance, Fibromyalgia Impact Questionnaire [FIQ], Beck Depression Inventory [BDI], Beck Anxiety Inventory [BAI], and the CDT of the subjects were evaluated. The CDT method used was that of Watson, Shulman, and Sunderland. Results There were no significant differences between the patients and the HNCs on demographic characteristics [P>0.05]. The FMS patients had statistically significant lower scores in three different clock scoring methods than the HNC group [P<0.005]. The Shulman scores and the Sunderland scores were significantly correlated with age or pain intensity in FMS patients [-0.27≤ r ≤-0.34, P<0.05]. There were no correlations between the CDT scores and educational level, Fibromyalgia Impact QuestionnaireIQ, Beck Depression Inventory, or Beck Anxiety Inventory scores [P>0.05].Conclusions The results of the present study showed that FMS patients had impaired cognitive performance when compared with the HNCs. Poor cognitive performance was related to only advanced age and high pain intensity. © 2012 Informa Healthcare USA, Inc.