Background: Coronary artery ectasia (CAE) is characterized by dilation of an arterial segment to a diameter ≥1.5 times that of the adjacent normal coronary artery, 10%–20% of CAE have been described in association with inflammatory or connective tissue diseases. The underlying mechanisms of ectasia formation are not yet entirely known, so the aim is to assess the validity of the high sensitivity C reactive proteins (Hs CRP) and the hematological parameters (platelet to lymphocyte ratio [PLR], mean platelet volume [MPV], and neutrophil to lymphocyte ratio [NLR]) to predict CAE. Patients and Methods: 60 patients with chronic stable angina were classified into three groups as follows: Group 1: CAE without coexisting atherosclerotic coronary arteries (20 patients), Group 2: CAE with coexisting atherosclerotic coronary arteries (20 patients), and Group 3: Normal coronary angiography (20 patients) as control group. Our patients were submitted to: (1) complete history taking (2) thorough clinical examination (3) electrocardiography (4) laboratory investigation with special interest in complete blood picture and Hs CRP (5) transthoracic echocardiography (6) coronary angiography. Markis classification was used for classification of CAE. Results: (1) NLR ≥2.65 can predict CAE with sensitivity 52.5% and specificity 100% (P < 0.001). (2) PLR ≥110.5 can predict CAE with sensitivity 82.5% and specificity 60% (P = 0.001). (3) MPV ≥8.25 can predict CAE with sensitivity 72.5% and specificity 55% (P = 0.007). (4) Hs CRP ≥2.35 mg/dl can predict CAE with sensitivity 95% and specificity 85% (P < 0.001). Conclusion: NLR, MPV, PLR, and Hs CRP can predict CAE. They are available, cheap, and easily calculated. Keywords: Coronary ectasia, high sensitivity C reactive protein, complete blood picture