The exploitation of chitinous materials seems to be an infinite treasure. The oligosaccharides of chitin/chitosan, prepared by hydrolyzing chitin/chitosan with chitinase/chitosanase, have various potential applications in the fields of food, agricultural, and pharmaceutical industries. Almost all of the chitinase/chitosanases-producing strains use chitin/chitosan (or colloidal chitin/chitosan) as a major carbon source. However, the preparation of chitin involves demineralization and deproteinization of shellfish waste with the use of strong acids or bases. The utilization of shellfish waste as the sole carbon/nitrogen source not only solves environmental problems but also decreases the production costs of microbial chitinases. To further enhance the utilization of chitin-containing seafood processing wastes, we have recently investigated the bioconversion of shellfish chitin wastes (shrimp shell, crab shell, and squid pen) for the production of enzymes and bioactive materials. Rather than attempting to review the literature, this paper summarized our recently published works in the field of microbial reclamation of these unutilized marine bioresources.