The suitability of various peroxide initiators for a radical polymerization-based self-healing system is evaluated The initiators are compared using previously established criteria in the design of ring opening metathesis polymerization-based self-healing systems Benzoyl peroxide (BPO) emerges as the best performing initiator across the range of evaluation criteria. Epoxy vinyl ester resin samples prepared with microcapsules containing BPO exhibited upwards of 80% healing efficiency in preliminary tests in which a mixture of acrylic monomers and tertiary amine activator was injected into the crack plane of the sample after the initial fracture. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A Polym Chem 48 2698-2708, 2010