A 67-year-old female was admitted to our hospital with status asthmaticus. Serum alkaline phosphatase (ALP) level was elevated and ALP-linked immunoglobulins (ALP-Igs) were detected by ALP isozyme analysis. Treatment with prednisolone resulted in improvement of her asthmatic symptoms and serum ALP level. Thereafter, elevations of serum ALP and ALP-Igs levels were seen whenever she had an asthmatic attack. She had no manifestations of autoimmune diseases. Changes in ALP-Igs levels in association with asthmatic activity suggested that ALP-Igs were related to the pathogenesis of bronchial asthma in this case.