To evaluate a model of shared decision-making for asthma treatment, appropriate to the needs of African American, Latino, Chinese, and other Asian and low income Caucasian patients to adherence to asthma controller medications in a two-year randomized clinical trial in 302 minority and low-income adults, 18-70 years of age, with suboptimally controlled, persistent asthma, paralleling a simultaneous evaluation being conducted in 311 Caucasian and Asian/Pacific Island adults, (total n=613), and to examine psychological mechanisms mediating the effects of the intervention on adherence and of adherence on asthma outcomes.