The effects of solid state fermentation on some physical characteristics, proximate and amino acid profile of post-harvest cowpea (Virgna unguiculata (L) Walp) leaves were investigated. Pulverized samples of the post-harvest materials were incubated at 260C for 96 hours, followed by urea and trichloroacetic acid treatments. Triplicate samples of fermented and unfermented materials were subjected to standard procedures to determine variations in weight, pH, proximate and amino acids profile. There was a reduction in weight, which was significant (p<0.05) with increase in fermentation time. pH stabilized at 6.62 and 6.65 at 96 hours of fermentation (HOF), before and after urea treatment, respectively. Fermented samples showed significant increase (p<0.05) in crude protein (37.30%), crude fat (95.69%), total ash (75.73%) and nitrogen- free extract (NFE) (5.00%) over the unfermented ones. However there were percentage reductions in crude fibre (46.60%) and moisture content (61.95%) after fermentation. The Total Amino Acids (TAA) increased from 49.64 ± 0.87 to 98.90 ± 1.70 with a general increase in all amino acids except proline and cysteine having 12.72% and 10.06% as percentage reductions, respectively. Some essential amino acids (methionine, phenylalanine and tyrosine) and non-essential amino acids (serine and proline) were limiting. The findings unveiled the feed supplement potentials of the fermented materials for use in livestock and pharmaceutical industries in Nigeria. Keywords: Fermentation, Nutritional Value, Post-Harvest, Cowpea