Cardiovascular diseases (CVDs), predominant global disabilities, are solely responsible for causing a significant number of deaths annually. The arising issues of conventional therapeutics, such as high insufficiency in reducing disease progression, unpleasant side effects, etc., have made CVDs a significant clinical challenge. Henceforth, the exploration of newer technologies and strategies for CVD management has become a need of present times. Recently, CVDs have become a major area of focus for medical, scientific and technological development. One such area of particular interest is an advancement of nanoparticle drug delivery systems for targeting CVDs, which offers a bouquet of positive attributes such as a high - targeted approach for specific disease sites, drug bioavailability and functional payloads. The present article mainly emphasis on the growing concept of ‘theranostic nanoparticles or nanotheranostics’ in the field of CVDs. The term ‘Theranostic’ combinedly refers to the union of diagnostics and therapeutics, with the purpose of enhancing the safety and efficacy of the treatment. Although it is still in its infancy stage for cardiovascular complications, the idea of theranostics has already been applied in the field of oncology and is giving fruitful results as well. The present chapter gives its description in the field of diagnosis as well as therapeutics, which may improve the status of nanomedical research in CVDs.