Objectives: To evaluate differences in the number and type of drug therapy problems (DTPs) identified by pharmacists with and without access to patients' primary care health records; determine the confidence level of pharmacists in their assessment of DTPs with and without access to health records; and determine the type of information pharmacists need to confirm their assessment. Methods: The study design was an exploratory and comparative evaluation of comprehensive medication management assessments. Pharmacists initially completed patient assessments without access to the patient's primary care health record. Pharmacists documented the visit according to the standard of care and documented the assessment in a standardized study form. Pharmacists then reviewed the patient's primary care health record and documented a revised assessment in the standardized study form. The standardized form included sections about the number of DTPs, the classification of DTPs, the pharmacist's confidence level in identifying DTPs, and the information needed to increase the pharmacist's confidence level in identifying DTPs. Results: Pharmacists evaluated 24 patients and identified 132 DTPs. After reviewing patients' primary care health records, 31 DTPs were deemed "false DTPs," 3 DTPs were recategorized, and 9 new DTPs were identified. Practitioner confidence levels in DTP determination improved after reviewing patients' primary care health records. The health information most frequently identified as desirable after the initial review was laboratory tests. Conclusion: Pharmacists identified more DTPs with lower confidence levels without access to patients' primary care health records. Fewer DTPs were deemed "confirmed DTPs" and confidence in the practitioners' assessments improved after review of the primary care health records. Access to primary care health records can help community pharmacists build an efficient and comprehensive medication management practice.