OBJECTIVES: The purpose of the study was to calculate primary medication non-adherence (PMN), using the Pharmacy Quality Alliance's  (PQA) quality measure with retail pharmacy transaction data.   Primary non-adherence is an instance whereby patients fail to initiate a pharmacotherapy regimen following a recommendation by a physician or other health care provider (a prescription).  METHODS: De-identified, pharmacy transactional data for calendar years 2010 and 2011 from 100 pharmacies of a pharmacy grocery chain were used.  Primary medication non-adherence was defined as when a new medication was prescribed for a patient age 18 or older, but was not obtained from the pharmacy within 30 days.  A set list of chronic medications was constructed that would warrant a patient needing to pick the medication up in a timely manner to begin therapy.  Additionally, only electronic prescriptions were assessed as the data captured for prescription origination date and medication pickup date could not be genuinely accounted for in paper prescriptions.  A prescription was categorized as new drug therapy if the medicine prescribed (or its generic equivalent) had not been filled for the patient by the pharmacy during the prior 180 days.  If the prescription was deemed to be a newly initiated drug therapy, it was included in the denominator for the measure.  The numerator was populated when a newly initiated drug therapy or its therapeutic equivalent was not filled within 30 days of the prescription’s origination date.   RESULTS: Using the PQA-developed PMN measure, these 100 pharmacies had an overall PMN rate of 9.3%.  The measure could be calculated using the pharmacy transaction data; however, some adjustments (e.g., assumption that patient did not receive drug at another pharmacy) had to be made.  CONCLUSIONS: Retail pharmacy data can be used to measure quality indicators, like PMN.  These measures will have limitations, as do other quality indicator measures.