This algorithm on the diagnosis and treatment of asthma is intended to complement and update the previously published Practice Parameters for the Diagnosis and Treatment of Asthma. Both documents were developed by the Joint Task Force on Practice Parameters, representing the AAAAI, ACAAI, and the JCAAI. The authors of this asthma algorithm have attempted to include all the elements essential for the diagnosis and care of patients with asthma. Every effort was made to keep the algorithm clear and concise, yet thorough and complete (Fig 1). Each component of the algorithm is elaborated further in a brief annotation. For further discussion, the reader is referred to the more extensive Practice Parameters for the Diagnosis and Treatment of Asthma.