Crosslinkable interpolymer complexes of novolac resin and poly(ethylene oxide) (PEG) were prepared by mutual mixing ethanol solutions of novolac and PEG. Fourier transform infrared (FTIR) studies revealed that the driving force for the formation of novolac/PEO complex is hydrogen bonding interaction between the hydroxyl groups of novolac and the ether oxygens of PEO. The morphology and thermal properties of the complexes before and after curing were investigated by optical microscopy and differential scanning calorimetry (DSC). It was found that the uncured novolac/PEO complexes had a single composition-dependent glass transition temperature (T-g). The curing with 15 wt % hexamine (HMTA) (relative to novolac content) resulted in disappearing of T-g behaviour for both the neat novolac and the novolac-rich complexes, owing to less mobility of the novolac chain segments. The melting temperature (T-m) and crystallization rate of the HMTA-cured novolac/PEO complexes decreased with increasing novolac content, and no T-m was observed for the cured complexes with PEO content less than 50%.