Abstract: A relatively unknown leguminous (Cassia fistula) seeds were processed to full fat and defatted seed flours and the chemical and functional properties of seed flour were investigated using standard methods. Results showed the following respective values for FCF and DCF: Fat 6.68 and 0.39%, ash 4.52 and 4.71%, protein 26.25 and 28.09%, fibre 7.47 and 7.68%, carbohydrate 49.80 and 53.44%, moisture content 5.28 and 5.69%. The respective mineral contents (mg/kg) were P 1.52 and 1.76, Zn 270.67 and 241.82, Fe 179.529 and 242.50, Mn 37.21 and 41.73, Mg 947.38 and 896.00, Na 118.42 and 145.31, Ca 924.99 and 1001.20, K 837.61 and 899.18. The respective phytic acid and tannin contents were 0.26 and 0.21%; 7.70 and 8.18%. The water absorption capacity, oil absorption capacity, emulsion capacity, least gelation capacity, foaming capacity and foaming stability (after 4 hours) of FCF and DCF were: 512 and 558%, 216.20 and 218.08%, 40 and 20%, 10 and 8% (m/v), 33.33 and 37.25%, 27.45 and 29.49% respectively. The protein solubility of FCF and DCF was least between pH 4 and highest between pH 7-10. Defatting significantly influenced the chemical composition and functional properties of CF.