From February 1988 to January 1990, 118 fine-needle diagnostic punctures of the gallbladder (DPG) were performed under continuous ultrasound (US) guidance on symptomatic patients with gallstones. The first attempt at gallbladder puncture and aspiration was successful in every patient with use of a 22-gauge needle and continuous US visualization of the needle tip. The aspirated volume varied between 3 and 88 mL (average +/- standard deviation, 25.0 mL +/- 15.3). Biliary analysis revealed an elevation of the cholesterol saturation index in patients with cholesterol gallstones (attenuation at computed tomographic examination of 50 HU or less) relative to that in patients with pigment stones (attenuation more than 50 HU) (1.3 +/- 0.2 vs 1.0 +/- 0.1, P less than .05). The nucleation time was prolonged in patients with pigment stones (19.3 days +/- 3.5 vs 1.8 days +/- 0.8 for patients with cholesterol stones, P less than .001). All patients remained hospitalized for 24 hours after DPG and were reexamined on an outpatient basis at 1 and 3 months thereafter. No complications were detected during either short-term observation or long-term follow-up. The authors conclude that DPG is a safe and valuable technique in the diagnostic work-up of gallstone patients to establish their suitability for nonoperative treatment.