We examined the effect of two β2-adrenoreceptor (β2AR) polymorphisms (A46G and C79G) in asthmatics presenting to the Emergency Department (ED) in relation to their response to standard therapy measured by change in Forced Expiratory Volume at one second (FEV1). Our hypothesis was that the polymorphisms in the β2AR gene would predict clinical response to therapy with 46G and 79C displaying decreased response to inhaled therapy.