Background: Coronary artery dominance is important for management of LMCA disease during Percutaneous coronary interventions involving LMCA. Prevalence of left dominant coronary circulation is 8 % – 10 % according to previous studies. This makes the left dominant coronary circulation which supplies 100 % of left ventricular mass at more risk during MI and during PCI. We attempted to analyse coronary artery dimension with reference to its dominance. Methods: In patients who were admitted in cardiology department and underwent CAG as per standard guidelines. LMCA dimensions and bifurcation angle of left and right dominant circulation were analysed by standard QCA in cardiac catheterisation lab. Results: The average diameter of left dominant LMCA is 5.49 mm (2.9 mm – 9.1 mm) compared to 5.08 mm (3.4 mm – 6.4 mm) of right dominant system. The average length and bifurcation angle of left dominant LMCA were 10.1 mm and 83.1 degree compared to 11.8 mm and 94 degree of right dominant LMCA. Conclusions: We have observed that left dominant LMCA was having relatively larger diameter, shorter length and narrow bifurcation angle compared to right dominant LMCA.