The water-uptake behavior of jute fabric and its composites with polycarbonate and polypropylene was monitor by a digital neutron radiography technique. The thermal neutron radiography facility of neutron transmission radiography (NEUTRA) at spallation source (SINQ) of the Paul Scherrer Institute was used for this work. The internal defects, such as voids, cracks, and inhomogeneity, of the composites were studied. The water-uptake behavior of the jute fiber was also studied with a digital neutron radiography technique. The natural jute fiber showed higher water absorption than the composites. No voids or inclusions in these composites were observed. Moreover, both the Jute and polymer were uniformly distributed and well mixed with the polymer matrix. (c) 2007 Wiley Periodicals, Inc.