Dynamic mechanical and thermal behavior of polyester composites reinforced with enzyme and NaOH-treated jute woven fabrics were studied. Dynamic properties such as storage modulus (E), loss modulus (E) and damping parameter (tan ) were determined in a single-cantilever bending mode. The storage modulus of the composites increased up to 110% and 130% with enzymatic and NaOH treatments, respectively. The composites reinforced with NaOH and enzyme-treated fibers showed a shift in loss modulus to a higher region when compared to untreated fiber composites. This was attributed to the increased immobilization of polymer matrix at the fiber-matrix interface as a result of pre-treatments. Tan pick values of the samples with treated and untreated jute fibers are fairly close indicating that all the samples showed very similar energy damping behavior. The derivative thermogravimetric and differential scanning calorimetry curves indicated that the thermal stability of the composites slightly decreased in the case of NaOH and enzyme treatments. Scanning electron microscopy pictures revealed a stronger fiber-matrix adhesion in composites with enzyme-treated fibers when compared to untreated fiber composites.