Many cases of recurrent noncardiac chest pain are considered to be of esophageal origin. The mechanism of this pain is poorly understood and only rarely appears related to abnormal esophageal contractions observed during manometry. We studied the response to intraesophageal balloon distention in 30 patients with noncardiac chest pain (mean age 52 yr) and 30 controls (mean age 41 yr). A polyvinyl balloon (length 30 mm; maximum diameter after 10-ml distention, 25 mm) was positioned 10 cm above the lower esophageal sphincter and inflated with progressively larger volumes of air (each increase = 1 ml). Chest pain was correlated with balloon volumes and pressures, esophageal contractions 5 cm above the balloon, and electrocardiogram changes. Results were as follows: 18 of 30 (60%) patients and 6 of 30 (20%) controls (p less than 0.005) experienced chest pain. Electrocardiogram changes of ischemia were not seen. Neither balloon pressures nor esophageal contractions above the balloon differed significantly during pain in the controls or patients. As assessed by pressure-volume curves, esophageal tone was also similar in all subjects regardless of pain production. Patients were more sensitive to smaller volumes of balloon distention; 15 of 18 patients had chest pain at less than or equal to 8 ml volume while controls only noted chest pain at greater than or equal to 9 ml volume. We therefore arrived at the following conclusions: esophageal balloon distention may provide a nonpharmacologic provocative test for esophageal chest pain; and the mechanism of chest pain in these patients may be related to lower pain threshold to balloon distention, which is independent of esophageal contractions.