The Clinical Practice Research Datalink (CPRD) is a comprehensive primary care database in the UK, covering over 11.3 million patients from 674 practices. It includes data on demographics, symptoms, tests, diagnoses, therapies, health-related behaviors, and referrals to secondary care. The CPRD is widely used for epidemiological research, with over 1000 studies published in peer-reviewed journals. Key strengths include broad coverage, large size, long-term follow-up, representativeness, and high data quality. However, challenges include variable data completeness, misclassification, and the need for extensive data processing. The CPRD has been used to investigate various health outcomes, such as the association between MMR vaccine and autism, and the risk of fractures with oral corticosteroid use. Researchers must be aware of the complexities of routinely collected electronic health records and manage data quality issues carefully.The Clinical Practice Research Datalink (CPRD) is a comprehensive primary care database in the UK, covering over 11.3 million patients from 674 practices. It includes data on demographics, symptoms, tests, diagnoses, therapies, health-related behaviors, and referrals to secondary care. The CPRD is widely used for epidemiological research, with over 1000 studies published in peer-reviewed journals. Key strengths include broad coverage, large size, long-term follow-up, representativeness, and high data quality. However, challenges include variable data completeness, misclassification, and the need for extensive data processing. The CPRD has been used to investigate various health outcomes, such as the association between MMR vaccine and autism, and the risk of fractures with oral corticosteroid use. Researchers must be aware of the complexities of routinely collected electronic health records and manage data quality issues carefully.