A nanocomposite based on nanoclay and resol that was modified with cardanol, a natural alkyl phenol, shows improvement for the glass-fiber-reinforced epoxy-composite system. Dispersion of the nanocomposite was investigated by X-ray, showing good results obtained by the in situ polymerization method. The mechanical properties of the final composites were improved by doping a 6 wt% of nanoclay in cardanol-modified-resol (CMR) into the epoxy matrix. The results show that a 15 wt% of CMR in epoxy is a most suitable ratio. Using polyamide as a curing agent instead of other traditional systems, such as anhydrides or amines for epoxy resin, overcame important limitations, further allowing for improved processability. The overall composite performance was enhanced. Additionally, the thermal stability of the system was investigated by thermal gravimetric analysis. (c) 2006 Wiley Periodicals, Inc.