Thus, this dissertation is comprised of three main sections: In the first section, the quality of different cassava leaf fractions obtained through mechanical pressing and ultrafiltration (UF) was evaluated. The results from the first study showed that cassava leaves and their juice fraction obtained after mechanical pressing as well as the sediment from centrifugation have the potential to be used as a protein source for food and feed, with the constraints of a higher TPC. The press cake, the solid fraction found after mechanical pressing, has good fiber and low phenolic content and could also be a good source for ruminant feeds. The UF process was successful in concentrating the protein in the retentate fraction without changing its nature. In the second section, a mild cassava leaf processing method was developed to remove cyanogenic compounds with minimum nutritional loss. Short thermal shredding combined with mechanical pressing was used to process the fresh cassava leaves. The protein quality of the press cake was better for feed than that of the juice. Mild cassava leaf processing resulted in a significant reduction of cyanide with minimal loss of nutrients in the leaves. In the third section, the effect of blanching and drying on the quality of four Ethiopian cassava varieties (Chichu, Hawassa-4, Quelle, and Kello) was studied. The results indicated that Ethiopian cassava leaf varieties have a good nutritional value and can be incorporated into the cereal-based diet in society as a protein source by applying the proper processing methods. Blanching resulted in better nutritional quality in some varieties.