Clopidogrel is a thienopyridine antiplatelet agent that inhibits adenosine diphosphate-dependent platelet activation and aggregation and is currently one of the most widely prescribed antiplatelet drugs for the treatment of symptomatic coronary artery disease. Several large clinical trials have demonstrated that it has a potent protective effect against adverse vascular events, including coronary, cerebral, and peripheral arterial disease. These clinical trials have reported among other clopidogrel's adverse effects, the adverse effects related to the central nervous system including headache and dizziness occurring in 7.6% and 6.2% of patients, respectively. Aim of this study is to detect possible effect of clopidogrel on human psychomotor performance in healthy volunteers. Using a double-blind, placebo-controlled, balanced, between-subject design at laboratories of the pharmacology department in Al-Mustansiryiah University Medical College, Baghdad, Iraq, during the academic year 2007-2008. Fifty-four young healthy volunteers were enrolled, they received either single oral doses of clopidogrel 37.5 mg (Plavix; Sanofi-Synthelabo) or placebo. Each treatment was given to 27 subjects. Measurements of psychomotor performance including the choice reaction time and its 2 components, recognition reaction time and movement reaction time, and the critical flicker fusion threshold using the computerized Leed psychomotor tester were performed just before medication and 2 hours afterward. No statistically significant difference in the parameters measured was detected among the two treatment groups. In this study, we found that single oral doses of clopidogrel in our group of normal healthy volunteers did not affect their psychomotor performance.