Alginate represents one of the most appealing biopolymers for pharmaceutical and biomedical applications. Alginate as a biomaterial for clinical use has been established, although not free from issues. Here we provide a critical review on some of the main recent advances in alginate research in drug delivery and its prominent role in cell microencapsulation for the treatment of diseases, such as type 1 diabetes mellitus. A brief description of the basic properties of the polymer will be provided as well. Based on our experience and contributions, as well as wide research in the field, the correlation between physicochemical and biological properties of alginate systems and clinical outcomes will be investigated and discussed to address the actual future clinical impact of alginatebased delivery strategies.