This study examined in 2005 t he impact of World Bank Expanded Programme for Root and Tuber Production (RTEP) on the poverty alleviation of peri-urban and rural communities in Benue State, Nigeria. It aimed at delineating causal effect disparity in poverty alleviation of two major producer communities. Data were collected from two hundred and eight (208) respondent s randomly drawn from ten (10) typically rural and ten (10) peri-urban communities. Simple descriptive statistics (percentages) and discriminant function analysis were used to analyze the collected data. The discriminant function was fitted on the poverty alleviation score to analyze causal and effect relationship. The study found disparities in valued output, quality of life, income and a homogeneous non-significant age disparity in both rural and peri-urban root and tuber crops producer communities. Major contributors to t he poverty alleviation were: Income realized from market able surplus (X3), distance in kilometers to the nearest urban market of best sales (X1), the kilometer distance traveled to evacuate produce (X2), with 5 5%, 15% and 10% contributions respectively in that sequence to the tot al discriminant score(Z) of 87%. Other contributory indicators were average revenue receipt per unit of root and tuber in the best market (X4), quality of life score (X5) and mobility score (X6). The study recommends that developing nations should re-focus their policy framework to provide better markets and marketing opportunities as well as improved transportation and communication infrastructures for the typically rural to accelerate poverty alleviation.