Abstract: The aim of the experiment was to assess the relatedness of 118 cowpea genotypes based on 16 morphological traits and to identify genotypes with unique traits for breeding purposes. The genotypes were from different parts of Ghana as well as International Institute of Tropical Agriculture in Nigeria and University of California Riverside in the United States of America. The phenotyping was done in the experimental farm of West Africa Centre for Crop Improvement, University of Ghana in April to June, 2011. Some of the traits included: terminal leaflet shape, number of seeds per pod, 100 seed weight, growth habit, days to flowering, plant pigmentation and number of pods per peduncle, based on key access and utilization descriptors for cowpea. Variability was observed in all of the 16 traits and was used to calculate dissimilarity between the genotypes with the method of Sokal and Sneath. The dissimilarity ranged from 7-100% with a mean of 43%. Factorial plot clustered the improved varieties together indicating that they have been selected based on similar traits pointing the importance of conservation in safeguarding genetic erosion. Diversity observed in the collection based on the 16 traits would be of use in selecting parents for genetic studies and breeding.