The poly(butylene succinate) (PBS) biodegradable composites reinforced with short coir fibres were fabricated by compression molding method. Effect of different fibre contents varying from 10 to 50 wt% on the mechanical and thermal properties of coir/PBS composites have been studied in terms of tensile and flexural properties, thermal stability, thermal expansion, dynamic mechanical properties, and microscopic observations. Tensile and flexural moduli of the composites were improved with the increase of fibre content up to 50 wt%. The results of thermogravimetric analysis showed that thermal stability of coir/PBS biodegradable composites is remarkably to be intermediate between the PBS resin and coir fibre depending on the fibre content. The thermomechanical stability of PBS resin is significantly improved by the addition of reinforcing coir fibres into the composite matrix. Dynamic mechanical analysis results also confirmed that the storage modulus of the composites was increased with increase in the loading of coir fibre, showing the stress transfers from the matrix to the fibre. The greatest value of storage modulus and lowest coefficient of thermal expansion obtained at 50 wt% fibre content in the present study. The fracture surface morphology of the composite specimens observed by scanning electron microscope (SEM) showed the weak bonding between untreated coir fibre and PBS matrix.