Aptamers, which are single-stranded DNA or RNA molecules, are increasingly recognized as important tools in diagnostics and therapeutics across various medical disciplines such as oncology, respiratory diseases, and neurological disorders. This review provides a comprehensive evaluation of the recent progress and obstacles encountered in the field of aptamer-based applications. Aptamers have shown promise in oncology for early cancer detection and targeted drug delivery, effectively reducing off-target effects. They also hold potential for significantly impacting the management of respiratory conditions such as asthma and Chronic Obstructive Pulmonary Disease (COPD) by selectively targeting cytokines and regulating the inflammatory response. In the realm of neurological disorders, aptamers offer novel methods by influencing the gut-brain axis and proposing potential approaches for early detection and specific therapy. Despite these notable benefits, persistent challenges remain in areas such as molecular stability, delivery mechanisms, and economic viability. This review offers a comprehensive overview of aptamer-based diagnostics and therapeutics while exploring potential avenues for future research.