In this paper we use a computable general equilibrium model to study the impact of a trade shock and a tariff reform on household poverty for an archetype developing country. Unlike other studies, we present the income distribution of each household group as a Beta statistical distribution. In contrast to other studies, this paper presents the poverty lines as being endogenous. With this specification, the poverty line will change following a variation in relative prices. With the new distributions and poverty line, the poverty levels of the base year are compared with the ex-post values. Foster, Greer and Thorbecke's (1984) poverty measures are used. We work with the Cameroon household survey data of 1995-96. We consider two scenarios. The first is a 30 percent fall in the world price of the country's export crop and the second is a reduction of 50 percent in the country's import tariffs. For the first simulation, results indicate a drop in all household incomes and a decrease in the poverty line. Unilateral trade liberalization also has negative consequences on all household incomes. As in the first simulation, the poverty line decreases with a unilateral trade liberalization. In the trade liberalization simulation, the poverty line effect counters the income effect in most cases analyzed. In the other simulation, the poverty line effect attenuates the decrease in the poverty measures.