The cyclin Dl gene, located on chromosome llql3, is frequently rea%anged in parathyroid neoplasms and amplified in some carcinomas of other organs. Recent studies have detected amplification of cyclin Dl and other markers on chromosome 1 lql3 (evaluated by Southern or slot blot assays) in ∼25–50% of squamous cell carcinomas of the esophagus and noted that amplification was associated with lessened survival time. We applied the technique of differentia] polymerase chain reaction to the evaluation of cyclin Dl gene amplification in squamous cell carcinomas of the esophagus. Cyclin Dl was found to be amplified in 10 of 45 (22%) primary tumors and three of 12 (25%) lymph node metastases. Lymph node metastases tended to be more common in patients with cyclin Dl amplification (70%) than in those without amplification (37%). In 36 patients with follow-up. cyclin Dl amplification was associated with decreased 1 year survival (28% vs. 59%). Cyclin Dl gene amplification in esophageal carcinomas can be evaluated by differential polymerase chain reaction and may provide useful prognostic information.