Com. epoxy and polyester resins were modified by addn. of com. halogen-free flame retardants (melamine polyphosphate and cyanurate, nano-sized montmorillonite, expandable graphite), cured and studied for O-2 index, heat release rate, mass loss during combustion, effective combustionheat and mech. properties. The addn. resulted in an increase in the O-2 index, and a decrease in the max. heat release rate and smoke formation. The mech. properties remained unchanged.