Abstract: Background and Objective: The annual wastes generated from rearing of cow and plantain plantation have been on the increase as a result of their higher demand. Hence, there is need to manage these wastes for human benefit. This study examined the contact time and mixing ratio effects of co-digestion of plantain pseudostem extract and cow dung on NPK value of produced organic fertilizer. Materials and Methods: Each of the samples was analyzed for nitrogen, phosphorus and potassium which were the major constituents of an organic fertilizer. Calibration curve was used to generate correlation between the absorbance obtained using UV spectrophotometer and concentration of potassium and phosphorus. Results: The results revealed presence of nitrogen, phosphorus and potassium with decrease in their respective concentrations as the pseudostem extract volume increases. However, each of them exhibited maximum value at specified contact time and plantain extract-cow dung mixing ratio. Nitrogen content decreased as contact time increased while concentrations of phosphorus and potassium increased with increasing contact time. Conclusion: Varying the values of plantain pseudostem extract-cow dung mixing ratio and contact time had significant effect on anaerobic micro-organisms’ activeness which thus affected the NPK value of produced fertilizer. Optimum NPK value could be obtained at specified contact time and mixing ratio. Digestate from anaerobic co-digestion digestate from plantain pseudostem sap and cow dung had revealed potential to be used as organic fertilizer as it contained some level of NPK.