The albumin to globulin ratio (AGR) is used as a prognostic marker in acute ischemic cardiovascular events. We investigated whether serum AGR, fibrinogen, and fibrinogen to albumin ratio (FAR) are related to the presence and severity of coronary artery disease (CAD). Patients who underwent coronary angiography procedures were analyzed retrospectively. The severity of CAD was assessed by the Gensini score. The study population (3031 patients; 1071 females and 1960 males) was divided into 3 tertiles based on AGR values. Gensini score, lipid levels, diabetes mellitus (DM), hypertension (HT), age, and fibrinogen level were higher in the low AGR group. Pearson correlation analysis showed that AGR (r = -0.068, P < .001) was negatively and fibrinogen (r = 0.187, P < .001) was positively correlated with the Gensini score. Male gender, HT, smoking, DM, age, high triglyceride (TG) level, low-density lipoprotein cholesterol (LDL-C) >160 mg/dL, estimated glomerular filtration rate (eGFR) <60 mL/min, and fibrinogen level >3.5 g/L were independent predictors of CAD. Male gender, age, eGFR, DM, LDL-C, TG, and FAR had an independent positive relation to the Gensini score. In conclusion, similar to traditional risk factors, plasma fibrinogen and albumin levels showed a close relation with the presence and severity of CAD.