Objectives: To report on barriers to and facilitators of medication adherence noted by asthma/chronic obstructive pulmonary disease (COPD) and diabetes patients who were both adherentand nonadherent to their medication regimen. Study Design: Survey. Methods: A random sample of 600 patients with asthma/COPD and 600 patients with diabetes were surveyed to assess factors that help and prevent medication adherence; 500 from each group had only 1 condition and 100 had other diseases. Half of each group were classifi ed as adherent based on a medication possession ratio of 80% or more. Data on disease condition and prescription use were obtained from relational, comprehensive databases in a large integrated health system. The survey was based on the ASK-20 questionnaire with additional questions on demographics and pharmacy use. Analyses included t tests or contingency tables with the Pearson χ2 or Fisher exact test. Results: The overall response rate was 70%. The majority of the population was white (88.5%) and employed full or part time. Most had competed high school and were married (65%). The most commonly cited barrier to medication adherence was having an irregular schedule (22%), followed by having to take pills with food (13%). Cost was also cited as a barrier, particularly by those with more than 1 disease condition. Patients reiterated the importance of building in medication taking as part of their daily routine, taking medication at the same time each day, and using aids such as pill containers. Conclusions: Routine appears to be a key factor in ensuring adherence.