The diversity of plants in the Field Genebank of the National Centre for Genetic Resources and Biotechnology (NACGRAB), Nigeria was assessed and reported in this publication. It was discovered tree species have the highest population, followed by the herbaceous plants. The dominant plant families in this field genebank are Caesalpiniaceae (20 representative species), Apocynaceae and Euphorbiaceae with 19 representatives, Mimosaceae and Papilionideae with 18; indicating high diversity of the species in these families in Nigeria. Furthermore, more than 80% of the plants are dicotyledonous. The Field Genebank has successfully conserved some endangered plant species in Nigeria and is still working on many others.