OBJECTIVES: Real world evidence (RWE) offers easily accessible information on treatments outside the realm of clinical trials. RWE is gaining significance as it explores various crucial outcomes pertaining to delivery of care in clinical practice. The objective of this study was to assess the trends and utilization of RWE based information in heart failure and asthma to support market access in the US. METHODS: A literature review was performed in PubMed to identify studies conducted on heart failure and asthma in a RWE setting in the US. The review included all studies in English, regardless of design. Studies were further stratified by type of RWE data sources, number of individuals, and type of research questions. RESULTS: In total, 805 studies (678 for heart failure indication and 127 for asthma indication) were included in the analyses. In heart failure, the majority of the studies were registries (54%) followed by medical records (16%), claims (15%), and other data sources (14%). However, in asthma, the majority of the studies used claims data (51%), followed by medical records, registries and other data sources which were represented in 20%, 10%, and 19% of studies, respectively. Common research questions addressed in those RWE data sources were epidemiology, burden of illness (humanistic and economic burden), treatment patterns and compliance, resource utilization, unmet needs and data on patient management. CONCLUSIONS: RWE covers a large patient pool unlike controlled trials. Multiple research questions can be addressed using RWE, though no single data source is likely to cover all questions. This study concluded that RWE may act as an important instrument to support market access strategies by filling data gaps and by providing more comprehensive real world results. These can be utilized further for the development of budget impact analysis models in the US.