Owing to their importance to the assessment of reinforced concrete structures, it is of great practical significance to predict the elastic moduli of concrete with interfacial cracks. The intention of this paper is to present an analytical solution for the elastic moduli of cracked concrete. According to the theory of stereology, the 2D scalar crack density is expressed as an explicit function of the aggregate area fraction and the central angle of interfacial cracks. For uniformly oriented and mutually interacted interfacial cracks, the effective medium method is used to derive the relative elastic moduli of cracked concrete. Based on the numerical results, it is found that the relative elastic moduli decrease with the increase of the aggregate area fraction and/or the central angle of interfacial cracks. It is also found that the relative elastic moduli are independent of the minimum aggregate diameter, the maximum aggregate diameter, and the aggregate gradation.