The first part of this investigation focused on the synthesis and characterization of a microencapsulated intumescent flame retardant (MIFR) agent. Two steps were used in the synthesis process. The structure was characterized by scanning electron microscopy, thermogravimetric anaylysis, and Fourier transform infrared spectroscopy. The addition of this MIFR agent into natural rubber (NR) led to an improvement in its physicomechanical and flame-retardant (FR) properties. The second part focused on the evaluation of such characteristics as cure characteristics, FR property, tensile properties, abrasion resistance, and dynamic mechanical analysis of MIFR filled NR composites. (c) 2007 Wiley Periodicals, Inc.