Home cage monitoring (HCM) systems enable continuous, automated observation of laboratory animals in their standard environment without human interference and are aligned with the 3Rs principle (reduction, refinement, replacement). They provide a variety of metrics, including locomotor activity, circadian patterns, feeding and drinking behaviors, which can support the development of new drugs by early detecting drug-related effects and potential toxicity. In the context of harmonized and standardized drug developmentDrug development, digital measures generated by HCM systems must undergo a process of validation, evaluating if they can be used as surrogates to biomarkers or additional, enhanced, early metrics. This chapter focuses on the relevance of HCM in preclinical studies in drug development, based not only on literature but also on real-case studies. The increased integration of HCM on a regular basis is expected in the following years with the emergence of more examples highlighting its inputs and maybe a consensus on how to use HCM technologies.