The authors prospectively evaluated the operating characteristics of the history and physical examination for ascites in a broad spectrum of hospitalized patients. The overall clinical evaluation produced a positive likelihood ratio = 37.7-83.3 when suggestive of ascites, a likelihood ratio = 2.23-3.42 when intermediate, and a negative likelihood ratio = 0.77-0.90 when not suggestive of ascites. Patients' perceptions of increased abdominal girth (positive likelihood ratio = 4.16) or recent weight gain (positive likelihood ratio = 3.20) increased the likelihood of ascites. The absence of subjective ankle swelling (negative likelihood ratio = 0.10) or increased abdominal girth (negative likelihood ratio = 0.17) decreased the likelihood of ascites. The positive likelihood ratios for a fluid wave = 9.6 and shifting dullness = 5.76 favored ascites, while the absence of bulging flanks (negative likelihood ratio = 0.12) or peripheral edema (negative likelihood ratio = 0.17) favored ascites the least. Thus, a routine history and physical examination are quantitatively useful in the clinical evaluation of ascites.