This chapter focuses on biomaterial-based particulate carriers, starting with issues that are common to all carriers: the needs that drive carrier-mediated therapy, essential carrier requirements and carrier mediated drug targeting. The advantages of biomaterial-based systems are then discussed in terms of the wide choice of raw materials, of utilizing nature's sites for targeting and of lowered risks for treatment safety. Also brought up are drawbacks for such carriers, in meeting requirements of pharmaceutical products and in potential adverse immune responses. The drawbacks are expected to be resolved in the future and even today the benefits of biomaterial-based carriers outweigh their downside. The concept of pathology-driven selection of carrier specifications, in particular, size and the route of administration, is introduced and discussed for a variety of pathologies. Specific examples are drawn from systemic, oral and local administrations for the treatment of cancer, diabetes and osteoarthritis. In conclusion, future prospects for biomaterial-based particulate drug carriers are deemed quite encouraging.