This study focused on evaluating the allelophatic attributes of Siam (Chromolaena odorata) and Mimosa (Mimosa pudica) herbs as possible bio herbicides for weed control in cowpea production. It was a deliberate effort aimed at deploying local on-farm natural resources into the crop production system of resource – poor Nigerian farmers instead of relying on the rather expensive agrochemical-based pest management. It was a potted experiment under screen house condition; where soil samples were bulked, thoroughly mixed, shade-dried and sieved through a 2-mm screen after which a composite sample was taken from the bulk soil for determination of some physico-chemical characteristics. There was separate layout for each of the weed herbs evaluated along with the Force-Uron herbicide formulation and a control (no application of herbicides and the weed herbs) to obtain seven (7) treatments. Cowpea seeds (Ife Brown variety) obtained from the Institute of Agricultural Research and Training (IAR&T), Moor plantation, Ibadan were sown into pre-moistened potted soil. Data were collected on weed pressure (Number and dry weed weight and cowpea growth parameter; height cm/plant, number leaf plant, weight of fresh and dry root and shoot. For the dry matter weight determination, samples of root and shoot were oven dried at 800C till constant weights are obtained. Data were analyzed using Statistical Package for the Social Sciences (SPSS) employing the method outlined by Steel and Torrie (1980). Treatment means were separated by Duncan Multiple Range Test (DMRT) at 5% level of significance. At 2WAP the most highly recommended treatment is 30kgMm/ha because at this rate there was the lowest number of weeds. At 4WAP the most highly recommended treatment is also 30kgMm/ha because at this rate of application the weeds were most effectively controlled. At 6WAP, 40kgMm/ha is recommended because of its weed control efficacy. At 8WAP treatment 40kgMm/ha is recommended because of its weed control efficacy at this period. For mimosa leaf meal at 2WAP the most highly recommended treatment is 50kgSm/ha because at this rate there was the lowest number of weeds. At 4WAP the most highly recommended treatment is 30kgSm/ha. At 6WAP however the most highly recommended treatment is 50kgSm/ha because at this rate the lowest number of weeds was recorded. Also at 8WAP the most highly recommended treatment is 50kgSm/ha.