Cowpea (Vigna unguiculata L.) is one of Indonesia local legumes that contain high protein. Cowpeas have anti-nutritional compound that can be reduced by cooking but cooking affected appearance of product. Incorporation of cowpea into peanut butter would potentially increase the use of local legumes. The aim of the research was to develop the partial replacement of cowpea to dehulled peanut paste in peanut butter processing. Observation of the effect of cowpea-peanut ratio (30:70, 40:60, 50:50) and type of oil (canola, soybean, and soybean oil) towards physicochemical properties, consumer acceptance, and nutritional composition were done. The best formulation was selected based on hedonic test in terms of color, taste, aroma, texture, viscosity, spreadability, and overall acceptance. Types of oil or nut ratio did not affect pH and color of peanut butter. Increasing ratio of cowpea decreased oil separation while type of oil did not effect oil separation. Interaction between nut ratio and types of oil gave a significant effect towards firmness and work of shear. Peanut butter, in which the raw materials were prepared by dry roasting method, made with ratio of 30:70 (cowpea:peanut) and soybean oil was selected as the best peanut butter formula. The best formulated peanut butter contained 20.97±0.37% of protein, 37.55±0.03% of fat, 2.58±0.57% of ash, 36.83±1.62% of carbohydrate, and 2.34±0.26% of moisture.