Objective　The aim of our study was to examine the utility of a mutielectrode basket catheter (MBC) in the mapping and Ablation of atrial tachycardias (ATs). Methods and Results　This study of ATs was conducted in 15 patients. The MBC recording and pacing capabilities, mapping performance and ablation with MBC was evaluated. Stable endocardial electrograms were recorded in 88±4% of electrodes. 64±5% electrode pairs could be used to stimulate the heart. Earliest endocardial activation was recorded from MBC and standard catheters were 41±9 and 45.9±8 m before the onset of P-wave,respectively (P=0.21). Ablation successed in 7 patients (87.5%). Conclusion　The MBC allows comprehensive and reliable endocardial mapping during ATs, which facilitates successful ablation in the patients with ATs.