Background: The efficacy of coronary angiography may be different in the right radial approach (RRA) and the left radial approach (LRA) due to more common vascular tortuosity in the RRA. The aim of the study was to determine whether LRA is a valid alternative for coronary angiography compared with RRA in Asian populations. Methods: This is a single-center, prospective, randomized controlled study. A total of 1,400 consecutive patients undergoing diagnostic coronary angiography were recruited and randomized to the RRA (number [n]=700) or LRA (n=700) group. The primary end point was total procedural duration. Secondary end points included fluoroscopy time, dose of radiation including cumulative air kerma and dose area product, contrast volume, and the incidence of vascular complications. Results: Coronary procedural success was achieved in 682 of 700 (97.4%) patients in the RRA and 680 of 700 (97.1%) in the LRA. The total procedural time (RRA 14.1 +/- 6.3 minutes versus LRA 13.2 +/- 6.0 minutes; P=0.006) and fluoroscopy time (RRA 3.8 +/- 3.3 minutes versus LRA 3.4 +/- 2.8 minutes; P=0.046) were significantly shorter via LRA in comparison to RRA. The percentage of hydrophilic wire use was also lower in the LRA group (14% [RRA] versus 10% [LRA]; P=0.016). The dose of radiation and contrast volume were not different between the two approaches. No cases of major bleeding and vascular complications requiring surgical intervention were reported, other than with one patient who experienced a symptomatic stroke and died in the RRA group compared with none in the LRA group. Conclusion: The LRA seems to be a feasible alternative for coronary angiography in Asian patients due to shorter procedural duration and fluoroscopy time, as well as less hydrophilic wire use in comparison to RRA.