The specialized structure and function of the lymphatics has stimulated considerable interest in both site-specific drug delivery to the lymph and lymphoid tissue, and delivery to the systemic circulation via lymphatic transport mechanisms. In this review, drug access to the lymphatic system from the vasculature or interstitium after parenteral administration, and from the gastrointestinal tract after enteral administration, is discussed. Macromolecular and lipophilic prodrug approaches to lymphatic delivery and the use of microparticulate systems such as microspheres, liposomes, and colloidal carbon are also examined and discussed.