In order to develop an easy method for measure the airborne C. japonica pollen allergen (Cry j 1) without any utensils or a special apparatus, we examined latex agglutination test for the purpose.The latex beads were reacted with the anti-Cry j 1 polyclonal antibody, and the beads were blocked with bovine serum albumin (sensitized beads). The measurement is as follows; two-fold diluted series of solutions of airborne samples are reacted with the sensitized beads, and the results are examined after 2 hrs.Agglutination was recognized with 5ng/ml Cry j 1 standard solution and 20pg/m3 of airborne samples.We have developed a simple method for measure the airborne Cry j 1 by use of latex agglutination test. The strong point of the method is 1) measurement is easy and does not affect the numbers of pollen, 2) do not need any utensils or a special apparatus, 3) measure the disease causative materials themselves.