Urea-formaldehyde microcapsules containing dicyclopentadiene (DCPD) were prepared by in-situ polymerization in an oil-in-water emulsion for self-healing of epoxy polymer. Microencapsulated DCPD healing agent was dispersed into epoxy matrix through ultrasonication to produce a polymer composite capable of self-healing and the effect of weight fraction of microcapsules on fracture properties of the composites was investigated. Composites having 0.5, 1. , and 1.5 wt. % of microcapsules were prepared. The virgin and healed fracture toughness of composite was measured using a single edge notched bending (SENB) specimen. An improvement of 78% in virgin fracture toughness was observed at 1.5 wt %. The fracture toughness of the composite after healing increased by 84%, 75% and 68% for the microcapsules wt.% of 0.5, 1 and 1.5 respectively in comparison to that of neat epoxy. Scanning electron microscopy of the fractured surface of composite was carried out to understand the various mechanisms responsible for the improvement in fracture toughness. © 2018 Elsevier Ltd. All rights reserved.