Predictions of the semi phenomenological Doi-Ohta theory for the rheology and morphology of immiscible blends are compared to experimental data of a 40/60 blend of PMMA/P alpha MSAN with a co-continuous structure. Since the Doi-Ohta theory actually was developed for co-continuous blends, published comparisons on droplet-matrix blends are not considered as adequate. It is verified how the polymeric constituents contribute to the blend response and it is shown how the phenomenological parameters of the Doi-Ohta theory can be determined. Subsequently, these parameters are used to predict the morphology evolution and theological response of the blend under oscillatory flow. The evolution of the storage modulus clearly reflects the changes in morphology of the blend over time and strain amplitude in agreement with the theoretical predictions. Below a critical strain amplitude the co-continuous structure will coarsen until a droplet-matrix morphology is generated but large strain amplitudes are effective enough to stop domain growth.