Background: Transradial single catheter approach for both coronary imaging using multipurpose and Amplatz left catheter has been studied. Recently, both coronary visualization by Judkins catheter was introduced. Therefore, we evaluated the usefulness of this method. Methods: From November 2002 to June 2004, 592 patients (male:393, mean age 59짹11 years old) were enrolled in the study. Coronary angiography was randomly assigned to use 3 different types of catheter (multipurpose, Amplatz left and Judkins left) in 3 different cardiologists. One of them is an expert transradialist and the other 2 trainees have experience of more than 300 cases of transradial coronary angiography. Total procedure time, fluoroscopic time and success rate in each methods are compared. Also, difference in procedural parameters of the examiner were compared. Results: Data for 3 different catheters were listed in the table. Procedure time and fluoroscopic time was significantly shorter in transradial expert compared to trainees. Also, success rate in transradial expert is higher than trainees. Conclusion: Transradial single catheter coronary imaging by Judkins left is an useful alternative to the conventional approach. Individual factors affected the success rate and procedure time.