Objective To compare the volume of the basal ganglia in patients with Tourette syndrome(T S) and the normal volunteers and to explore the underlying anatomical basis of TS.Methods Thirty-one cases of TS (TS subjects),31 gender and age-matched subjects (the control subjects) were examined on a 3.0 T MRI system.The volume of the caudate nucleus,globus pallidus,putamen of the two sides and the brain volume were measured with volume analysis software,and the data were normalized according to the individual brain volume.Statistical analysis was performed using t test to compare between the TS subjects and the controls.Results The volume of the both sides of the caudate nucleus,putamen and globus pallidus of TS subjects were (4.11 ±0.12) and (3.76 ±0.11),(2.28 ±0.12)and(2.35 ±0.28),(4.98 ±0.20) and (4.89 ±0.31)cm3,while they were (4.88 ±0.19) and (4.30 ±0.12),(2.28 ±0.12)and (2.35 ± 0.28),(4.98 ± 0.20) and (4.89 ± 0.31) cm3 in the controls,respectively.There were significant differences in the bilateral caudate nucleus and globus pallidus between the TS subjects and control subjects (t =2.97,1.74,3.72,3.93,P ＜ 0.05),but there were no significant differences of the volume in the bilateral putamen between the TS and control subjects(t =0.47,1.31,P ＞0.05).The volume was not significantly different between the left and right caudate nucleus in the TS subjects (t =1.81,P ＞0.05),but the left volume of the caudate nucleus was bigger in the control subjects compared with the right volume,however,there was significant difference between the bilateral caudate nucleus in the control subjects (t =2.34,P ＜ 0.05).There were no differences of volume between the bilateral globus pallidus and putamen in both the TS and control subjects (t =1.12,1.44,1.68,0.38,P ＞ 0.05).Conclusion The abnormal volume of caudate nucleus,putamen,and the globus pallidus may be involved in the pathogenesis of TS.