Taking the medicines as prescribed and continuing the prescription regimen as advised is defined as “medication adherence”. Nonadherence is a significant hurdle to improve patient health outcomes and also has negative repercussions on the healthcare systems, clinicians and other stakeholders involved in healthcare. Estimating the magnitude of medication nonadherence is a crucial step to improve adherence. Though there are many measures, none of them can completely capture nonadherence in its entirety because of inherent drawbacks of each measure. While ‘subjective’ measures help to understand the barriers to adherence, ‘objective’ measures can provide a precise measure of patient’s medication-taking behaviour. Hence, a multi-measure approach is currently recommended to provide a better measure of nonadherence.