This chapter describes a chemical method for mutational analysis of the human glucocorticoid receptor (hGR) cDNA. Corticosteroid-resistant (CR) asthma is associated with in vitro and in vivo defects in mononuclear cell function (1). In addition, molecular studies using these cells have revealed that there is reduced binding of the hGR to its DNA recognition site, the glucocorticoid response element, compared to corticosteroid-sensitive (CS) controls (2). The authors therefore postulated that a point mutation of the primary structure of the GR was responsible for this functional defect, necessitating a method that would be sensitive enough to detect single-base-pair (bp) mismatches.