Public health officials in New Hampshire identified a cluster of three Salmonella Oranienburg cases that matched by pulsed field gel electrophoresis (PFGE), a genetic fingerprinting technique. Two of the persons were co-workers at a long-term care facility, and one was a patron of the cafeteria of that facility. The PFGE pattern was unusual and prompted the Centers for Disease Control and Prevention (CDC) to look for other recently reported cases that matched that pattern. Thirty-eight additional cases were identified in ten states and Ontario, Canada. A case control study was conducted to determine risk factors for infection. Illness was associated with eating fruit salad at a health care facility or grocery store. The salads eaten were composed of a variety of fruits; cantaloupe and honeydew melon were commonly ingredients in the salads. Illness was not associated with single fruit, fruit salads. Among thirteen health-care facilities with case-patients, the source of the melon was identified for eleven of the facilities. The melon served was precut cantaloupe and honeydew purchased from a single processing plant in Canada. The Canadian Food Inspection Agency did not identify any improper practices. The plant received fruit from a variety of farms. A traceback of the melon suggested that the fruit originated in the United States, however no specific source farm could be identified. Salmonella was never isolated from the fruit salad samples that were tested.