Recent results indicate that the adjusted DNA Index (aDI), a measure of nuclear DNA content, is a significant prognostic factor for patients with advanced laryngeal cancer treated with surgery and radiation therapy. Because DNA aneuploidy is an indirect measure of the proliferative activity of a cell population, a study was conducted to examine differences in tumor response to induction chemotherapy based on aDI values. Pretreatment tumor specimens were obtained from 50 patients with stage III and IV laryngeal squamous cell carcinoma who underwent induction chemotherapy (cisplatin/5-FU). With the use of computerized cytomorphometry, DNA content and nuclear area were measured and associations with tumor site, stage, chemotherapy response, tumor recurrence, and survival were examined. An elevated aDI was more frequent in patients with a chemotherapeutic response (p = 0.08), and mean aDI was higher among the complete responders. There were no complete responders among patients with a low aDI value (< 0.024). Neither aDI nor nuclear area correlated significantly with organ preservation or patient survival. Our results indicate that a complete response is more likely for patients with tumors with an elevated aDI and that pretreatment aDI may be useful in selecting high-risk patients who might benefit from chemotherapy.