PURPOSE: Polypharmacy-the use of multiple medications by a single patient-is an important issue associated with various adverse clinical outcomes and rising costs. It is also a topic rarely addressed by clinical guidelines. We used routine Scottish health records to address the lack of data on the prevalence of polypharmacy in the broader, adult primary care population, particularly in relation to long-term conditions. METHODS: We conducted a cross-sectional analysis of adult electronic primary healthcare records and used linear regression models to examine the association between the number of medicines prescribed regularly and both multimorbidity and specific clinical conditions, adjusting for age, gender and socioeconomic deprivation. RESULTS: Overall, 16.9 % of the adults assessed were receiving four to nine medications, and 4.6 % were receiving ten or more medications, increasing with age (28.6 and 7.4 %, respectively, in those aged 60-69 years; 51.8 and 18.6 %, respectively, in those aged ≥ 80 years), but relatively unaffected by gender or deprivation. Of those patients with two clinical conditions, 20.8 % were receiving four to nine medications, and 1.1 % were receiving ten or more medications; in those patients with six or more comorbidities, these values were 47.7 and 41.7 %, respectively. The number of medications varied considerably between clinical conditions, with cardiovascular conditions associated with the greatest number of additional medications. The accumulation of additional medicines was less with concordant conditions. CONCLUSIONS: Polypharmacy is common in UK primary care. The main factor associated with this is multimorbidity, although considerable variation exists between different conditions. The impact of clinical conditions on the number of medicines is generally less in the presence of co-existing concordant conditions.