Purpose The aim of this study was to evaluate the validity of lower limb chronic venous disease (CVD) diagnoses entered in a large electronic health record database in primary care in Catalonia, Spain; to investigate the reliability of these data for research purposes; and to estimate the prevalence and incidence of CVD, chronic venous insufficiency (CVI), and venous leg ulcer (VLU). Design Real‐world data analysis based on a large electronic health record database in primary care in Catalonia, Spain. Methods We used a primary care research database (Information System for the Development of Research in Primary Care SIDIAP), which contains anonymous data on some 5.8 million people from 279 primary care centers, accounting for more than 80% of the Catalonian population and 15% of the Spanish population. We evaluated the validity of the ICD‐10 codes for CVD in SIDIAP for 200 adult patients through the responses of 20 primary care physicians to a questionnaire. Findings The positive predictive value of CVD in SIDIAP was 89.95% (95% confidence interval CI 84.99–93.40). The prevalence rates for CVD, CVI, and VLU were 9.54% (95% CI 9.51–9.56), 3.87%, and 0.33%, respectively. The incidence rates for CVD, CVI, and VLU were 7.91/1,000 person‐years (95% CI 7.82–8.00), 3.37/1,000 person‐years (95% CI 3.31–3.43), and 0.23/1,000 person‐years (95% CI 0.21–0.24), respectively. Conclusions The Catalonian SIDIAP database contains valid CVD diagnoses. The prevalence and incidence rates found using real‐world data are low compared with those in the literature, possibly because CVD is an underdiagnosed entity. Clinical Relevance Real‐world data can inform clinicians on lower limb venous health in a population, show changes as individuals age, and reveal aspects where healthcare can be improved.