A field experiment was conducted during the rainy seasons of 2009 and 2010 at the National Root Crops Research Institute Sub-Station, Otobi to assess the nodulation and nitrogen-fixing potentials of nine newly introduced extra-short - and short - maturing cowpea genotypes. These genotypes were: IT00K-1217, IT04-221-1, IT03K-378-4, IT03K-316-1, IT99K-377-1, IT98K-692, IT04K-217-5, IT03K-324-9, and IT03K-351-1) obtained from International Institute for Tropical Agriculture (IITA), along with Ife Brown (a short – duration local check). The experiment was a split-plot laid out in randomized complete block design with three replications. The main plot treatments comprised of two cropping systems [(i) sole cropping-cowpea and maize (ii) intercropping-cowpea + maize].The sub-plot treatments were 10 cowpea genotypes. Estimation of Nitrogen (N) fixation in the cropping systems was determined by the N-difference method using maize as the non-fixing control. Significant differences in the number and biomass of nodules among cowpea varieties were observed. Total plant biomass varied mainly with variety of cowpea used in the intercropping systems and IT99k-377-1 produced the highest total plant biomass (3.18 t/ha), while IT00k-1217 gave the lowest (1.60 t/ha). N and P(Phosphorus) concentrations of all the cowpea genotypes were highest in the leaf and lowest in the roots. The nitrogen harvest index varied from 0.76-0.97 with a mean of 0.85. Nitrogen fixed by cowpea in the intercropping systems ranged from 11.40 - 51.70 kg/ha with an average of 33.90 kg/ha). IT00K-1217 had the lowest N fixation value (11.40 kg/ha) while IT99k-377-1 gave the highest (51.70 kg/ha). The mean N fixed by these extra-short - and short – duration cowpeas intercropped with maize was far below those reported for cowpea by other workers indicating that these cowpeas may not be suitable as soil ameliorants for inherent low fertility of the degraded /over-used soils in Otobi.