This report presents three cases of IgG4 related sclerosing disease complicated with chronic sclerosing sialadenitis. The clinical, radiographic and pathologic findings later suggested that the patients had chronic sclerosing sialadenitis. The submandibular gland tumour regressed in two patients. These patients were suspected to have Mikulicz's disease or Sjögren's syndrome, but the diagnostic criteria were not satisfied. The workup for chronic sclerosing sialadenitis revealed a significantly elevated value of serum IgG4. The patient was then diagnosed with IgG4 related sclerosing disease complicated with chronic sclerosing sialadenitis. After administering prednisolone to these patients, the serum IgG4 values decreased after 4 weeks. The current cases may represent a new category for Mikulicz's disease or Sjögren's syndrome as an IgG4 related sclerosing disease.