The aim was to evaluate the predictability of portal diameter (PD) in the diagnosis of esophageal varices (EV) and of large size EV (F3EV) in a large series of patients with cirrhosis. Two-hundred sixty-six persons with cirrhosis (M:F = 153:113; mean age 65.4 +/- 10 y) were studied by abdominal sonography and upper endoscopy. Portal hypertensive gastropathy (PHG) was found in 16.1% and EV was found in 60.9% of patients. Only Child's class (B vs. A: OR 3.4, p < 0.0001; C vs. A: OR 10.3, p < 0.0001; C vs. B: OR 3.1, p = 0.01) and age (OR 1.04, p = 0.03) were independent predictors of EV, whereas PD was not (p = 0.4). Child's class and age were also the only independent predictors of F3EV. Mean PD showed a slight and not significant increase in PHG patients compared with patients with negative endoscopy, a reduction in F1EV patients and then a progressive increase in F2EV and F3EV patients. Patients with PD <12 mm showed a significantly higher prevalence of F1-F2EV (p < 0.05) and a near-significant lower prevalence of endoscopies negative for EV (p = 0.06) than patients with 12 < or = PD < or = 13 mm. PD was not able to predict EV or F3EV in a large series of patients with cirrhosis. The oscillatory trend of PD, proceeding from patients with negative endoscopy to F3EV patients, seems to indicate that EV may unload portal pressure in the initial phases of portal hypertension.