Background: Stable coronary artery disease (CAD) is known to have an increased risk of cardiovascular events. Serum albumin (Alb) is reported as a useful risk-stratification tool in cardiovascular diseases such as acute coronary syndrome or heart failure. However, the association between Alb and stable CAD is unclear. Thus, we aimed to investigate the prognostic significance of Alb in patients with stable CAD. Methods and results: We analyzed the data of all patients admitted to Shinonoi General Hospital between October 2014 and October 2017 for newly diagnosed stable CAD, treated via elective percutaneous coronary intervention, with the exception of old myocardial infarction. We collected data, including Alb, at admission. The primary endpoint was major adverse cardiac events (MACE; defined as all-cause death, non-fatal myocardial infarction, non-fatal stroke). In 204 enrolled patients (median age, 73 years), during a median follow-up of 783 days, 28 experienced MACE. Alb was significantly lower in patients with MACE than in those without (p<0.001). In Kaplan-Meier analysis, low Alb predicted worse prognosis in MACE (p<0.001). In multivariate Cox regression analysis, low Alb levels independently predicted MACE (p<0.001) after adjusting for age and sex (HR 4.128 [95% CI 1.632–10.440], p = 0.003), or, age and C-reactive protein (HR 3.373 [95% CI 1.289–8.828], p = 0.013). Conclusions: Low Alb levels predicted MACE in patients with stable CAD.