During January--February 2001, eight cases of acute illness in the county of Ragusa, Italy, were reported to the Italian National Institute for Health (INIH) by the Milan Poison Control Center (MPCC) and were attributed to exposure to Dormex, a plant growth regulator with hydrogen cyanamide as the active ingredient. These cases were identified during a pilot project for acute pesticide-related illness surveillance. Subsequent active case finding at health-care clinics by the Ragusa Occupational Health Unit identified six additional cases. MPCC identified nine cases in other areas of Italy. Of the 23 cases of acute illness, 22 resulted from occupational exposure during mixing and/or applying of Dormex, and one was from unintentional ingestion. This report summarizes the investigation of these cases, which implicates a pesticide as the causative agent and demonstrates the usefulness of surveillance for detecting pesticide-related illnesses.