Green polymers from renewable monomers are attractive environmentally benign polymers in view of social feasibility. Recently the diversity of the green polymers from renewable monomers has extended vastly from soft elastomers to hard engineering plastics. Renewable monomers can be obtained mainly from plants and sometimes from animals, often via fermentation. Researchers have been seeking monomers in artificially grown crops, forestry wastes, and fermenter of microbial cultivation, with much knowledge in biology and biotechnology. Monomers to be used in polymer syntheses are required to have two or more functional groups, excepted unsaturated monomers having one carbon-carbon double bond, which can be linked together to form a polymer. These monomers are subjected to condensation polymerization and addition polymerization, sometimes after modification via chemical processes. In this review, polymers from triglycerides, essential oils, natural phenolic compounds, carbohydrates, or fermentation products are introduced. Polyesters, polyamides, polyurethanes and addition polymers synthesized from renewable monomers are developed for industrial applications.