Rheokinetic and phase separation behavior of diglycidylether of bisphenol-A-4,4＇-diaminodiphenyl methane epoxy mixtures, modified with a constant amount (15 wt %) of poly(methyl methacrylate) (PMMA), have been investigated. Stoichiometric epoxy/amine mixtures precured at 80 degrees C several times presented various levels of miscibility. Differential scanning calorimetry (DSC) and dynamic mechanic thermal analysis were used for rheokinetic studies of curing and also for testing the thermal behavior of the fully cured mixtures. Phase separation, through curing, was simultaneously studied by transmission optical microscopy and DSC, showing an excellent correlation between the results obtained with both techniques.