We have studied the phase behavior and theological property of the cubic phase and related gel emulsions in water/nonionic/dodecane systems. In the phase behavior study, it is pointed out that the formation of the discontinuous cubic phase (I-1) is not common in all nonionic surfactant systems; however, a cubic phase (I-1) with oil-swollen micelles or a cubic phase microemulsion is found in the water/C16EO6/dodecane system, which can solubilize large amount of oil. It was also observed that water/C16EO6/dodecane system forms stable gel emulsion. in the theological study we have found an anomalous behavior of the I-1 phase in the water/C12EO6/dodecane and the water/C16EO6/dodecane systems. In the water/C12EO6/dodecane system, the viscoelastic nature of the I-1 phase has been observed, which is shifted to the elastic nature with the addition of dodecane, whereas, highly elastic nature was observed in the water/C16EO6/dodecane system. In both the cases shear-thinning behavior were seen. The elastic modulus, G' and complex viscosity, |eta*| of the I-1 phase increase with the dodecane concentration in the water/C12EO6/dodecane system, whereas, decreasing trend have been observed in the water/C16EO6/dodecane system. This anomalous behavior is suggested due to the nonspherical shape of micelles or polydispersity of the micelles in the water/C16EO6/dodecane system. The theological behavior of the O/I-1 gel emulsion was also Studied in both the systems. (C) 2009 Elsevier Inc. All rights reserved.