Abstract: Cnidoscolus acontifolus (Americana leaf) leaves are used as soup condiment in Nigeria either in the processed or unprocessed forms. This study aims at assessing the effect of some post-harvest treatment on the nutrient, antinutrient and antioxidant potentials of the leafy vegetable. In this study fresh leaves of Cnidoscolus acontifolus were subjected to different food processing method such as soaking, blanching, abrasion with or without salt. The proximate, antinutrient (phytate and cyanide), minerals (Ca, Fe, Mg, Na, K, Zn and Mn), Vitamin C and total phenol content were subsequently determined. The result of the study shows that the unprocessed Cnidoscolus acontifolus leaf had 7.8% protein, 1.6% fat, 2.4% crude fibre, 2.3% ash and 83.4% moisture content. The total phenol (0.7%), phytate (479.5 mg/100g), mineral and vitamin C (535.6mg/100g) content were generally high, while the cyanide content was low. However, the various conventional food processing techniques caused a significant decrease (P<0.05) in the protein, vitamin C, cyanide and phytate content. While it caused a significant increase (P<0.05) in the fat and total phenol content of Cnidoscolus acontifolus leaf. In conclusion, the leaf of Cnidoscolus acontifolus has a very high nutrient, antinutrient, mineral and antioxidant potential; however the various conventional post-harvest treatments will cause a significant decrease (P<0.05) in the nutrient and antinutrient content, and same time caused a significant decrease in the antioxidant potential.