BACKGROUND: Previous studies have reported high rates of occupational injury and illness among workers in the tree fruit industry. However, many common and preventable risk factors and conditions in orchards have not been investigated. AIMS: To identify and rank risk conditions leading to workers' compensation claims among orchard workers with respect to frequency, severity and cost. METHODS: State Fund workers' compensation claims between 1996 and 2001 for orchard workers in the main tree fruit growing region of Washington were reviewed and categorized according to cause of injury. Descriptive analyses were performed to characterize claims by cause of injury. RESULTS: Of the 13,068 claims in the dataset, 4,020 (31%) were determined to be ladder-related injuries. Ladder-related claims accounted for nearly half (48%) of all 'compensable' claims (e.g. claims involving time loss, disability or 'loss of earning power' in addition to medical expenses). Claims related to ladders were not only the most frequent but also the most expensive collectively in terms of medical aid, time loss and other costs. On a per-claim basis, ladder-related injuries were among the most severe and costly reported injuries. Other common causes of injury among claims were branches and vegetation, structure and material and ground-related injuries. CONCLUSIONS: There is a strong and compelling need to develop interventions to reduce the number of ladder-related injuries in orchards.