Okpiye is a food condiment prepared by the fermentation ofProsopis africana seeds. The traditional process for the production and microbiological characteristics of the condiment were investigated. During laboratory fermentation that lasted 96h, the mesquite seeds underwent a natural fermentation that was characterised by the growth of microorganisms to 106–108 cfu/g. Several species of bacteria especiallyB. subtilis, B. licheniformis, B. megaterium, Staphylococcus epidermidis andMicrococcus spp were found to be the most actively involved organisms. However, significant contributions to the microbial ecology were made byEnterobacter cloacae andKlebsiella pneumoniae. Lactobacillus spp were present in low numbers towards the end of the fermentation. The presence ofProteus andPseudomonas spp in traditional fermented samples demonstrate the variability which may exist in the microflora of individual fermented samples. Variations in the important microbial groups show thatBacillus spp were the most prevalent species and occurred until the end of fermentation. Temperature, pH and titratable acidity varied with time and were influenced by the metabolic activities of the microorganisms.