Direct and indirect translog production functions provide cost share equations which are flexible and are consistent with microeconomic theory. This paper combines recent developments in the technique of estimating production and consumer demand equation systems and in computing the standard errors of the elasticities accurately in studying the demand for cereal products in Egypt. The gain in accuracy from not using the approximation method--commonly used in the literature--is presented theoretically and empirically. The data employed in this paper are Egyptian and are for wheat, maize, and rice; these are interpreted as factor inputs that produce a specific product which we will refer to as "cereals". Our findings show that the Allen elasticities of substitution (AES) between wheat and maize and wheat and rice exhibit significant (statistically) substitution. On the other hand, the relationship between maize and rice is independent based, again, on a lack of statistical significance. Indeed, there is fairly convincing evidence that rice is functionally weakly separable from wheat and maize. The overall findings suggest that the neoclassical model offers considerable promise for modeling the household's demand for cereals in Egypt.