Poor adherence to medication regimens may be contributing to the recent increase in asthma morbidity and mortality. We examined patient characteristics that may influence adherence to twice-daily inhaled steroid regimens. Fifty adults with moderate to severe asthma completed questionnaires examining sociodemographics, asthma severity, and health locus of control. Adherence was electronically monitored for 42 d. Following monitoring, patients' understanding of asthma pathophysiology and the function of inhaled corticosteroids were assessed. Patient beliefs about the effectiveness and convenience of these medications, and their perception of communications with their clinician were measured. Mean adherence was 63% +/- 38%; 54% of subjects recorded at least 70% of the prescribed number of inhaled-steroid actuations. Factors associated with poor adherence were less than 12 yr of formal education (p < 0. 001), poor patient-clinician communication (p < 0.001), household income less than $20,000 (p = 0.002), Spanish as primary language (p = 0.005), and minority status (p = 0.007). In a multiple logistic regression analysis, less than 12 yr of formal education (OR: 6.72; CI: 1.10 to 41.0) and poor patient-clinician communication (OR: 1.2; CI: 1.01 to 1.55) were independently associated with poor adherence. These results emphasize the importance of socioeconomic status and adequate patient-clinician communication for adherence to inhaled-steroid schedules.