In this paper, correlations are proposed to estimate the effective thermal conductivity of two-phase materials. For any a, Maxwell equation for 0.0 < c <= 0.10 and phase inverted Maxwell for 0.9 <= c <= 1 are considered. For concentrations between 10% and 90%, and low a (< 20), an equation based on the unit-cell approach (constant isotherms) is proposed. For a > 20, three correlations are proposed based on field solution approach which includes three alpha ranges viz. medium (20 < alpha <, 100), high (100 < alpha <= 1000) and very high (1000 < alpha). The predicted effective thermal conductivity of two-phase system is compared with well-established models. Comparison of the predicted values of the correlations with experimental results is also made. The predictions of effective thermal conductivity of twophase materials match well with the experimental values. (c) 2006 Elsevier Ltd. All rights reserved.