Objective: To study the results of percutaneous coronary intervention (PCI) and in-hospital outcomes in cardiac catheterization laboratory, Thammasat University Hospital since May, 2006 until April, 2009. Material and Method: This is the prospective, single-center study. The consecutive patients who underwent PCI in Thammasat University Hospital since May 2006 to April 2009 were recruited in the study. Clinical data, angiographic data, and inhospital outcomes were analyzed and demonstrated. Results: Six hundred and seventeen patients undergoing 755 PCI procedures were enrolled in the study. 62.70% were male and 37.30% were female. Mean age was 65.45 + 11.21 years (range 33-97 years) and 20.10% were more than 75 years old. The indications for PCI were non-ST segment-elevation acute coronary syndrome (NSTEACS) (41.72%), chronic stable angina (25.32%), acute ST segment elevation myocardial infarction (STEMI) (8.87%), staged PCI (15.76%). The other indications were heart failure, cardiomyopathy, post-cardiac arrest and etc. The procedure was single vessel PCI in 73.25% and multivessel PCI in 26.75% (double vessels PCI 24.64% and triple vessels PCI 2.11%). According to lesion locations, 45.21% were left anterior descending (LAD) artery lesions, 30.09% were right coronary artery (RCA) lesions, 23.28% were left circumflex (LCX) artery lesions, 1.19% were left main (LM) lesions and 0.24% were graft lesions. The overall angiographic success rate was 95.57%. During hospital stay the major adverse events developed as death in 0.93%, periprocedural myocardial infarction in 3.17%, emergency coronary artery bypass graft in 0.53%, and stroke in 0.26%. Conclusion: During the first three years of PCI experience in Thammasat University Hospital, the overall success rate was high with low in-hospital adverse outcomes.