A series of biocomposites were developed by reinforcing agar particles from red marine plant Gelidium robustum into poly(butylene adipate-co-terephatalate) (PBAT) using extrusion and injection molding technique. The effect of different content of agar (0, 10, 20, 30, and 40 wt%) on the physico-mechanical properties of the biocomposite was evaluated. The dynamic mechanical behavior of the composites was studied to determine the storage and loss modulus. The incorporation of agar particles into PBAT enhanced the tensile strength and modulus with a reduced percentage of elongation at break. A reduction in the mechanical loss factor (tan delta) was noticed with the addition of agar particles into PBAT. A reverse trend was noticed for storage and loss modulus. The thermogravimetric analysis revealed that the degradation temperature of PBAT-agar composites lies in between that of their individual components (agar and PBAT). An increase in melting (T-m) and crystallization (T-c) temperature of the biocomposites were noticed as agar particle content increased. The rheological study carried out by dynamic frequency experiments demonstrated that viscosity is increased with the presence of agar particles. The morphology of the biocomposites was analyzed using scanning electron microscope. POLYM. ENG. SCI., 49:1117-1126, 2009. (C) 2009 Society of Plastics Engineers