The study identified the players in the sweet orange value-chain and interviewed them to quantify postharvest losses incurred along the sweet orange value-chain in Rusitu Valley. A sample of 100 farmers in Rusitu Valley was selected using a snow balling sampling technique. A Value-Chain Priority Test was conducted to determine farmers’ priorities between oranges and bananas using a five point hedonic-scale. Interviewer administered questionnaires were used to gather socio-demographic data, sweet orange trading information, and farmers’ perceptions on the causes and estimation of postharvest losses in the Valley. The study estimated that postharvest losses of 36%, 3% and 42% occurred; in the field, during transportation and at the market, respectively. These amounted to a total of 81% postharvest losses with an estimated monetary value of US$ 11 003 126.40. There was a significant positive association (Pearson r = 0.29, p < 0.05) between the farmers’ score of pest and disease incidence in their sweet orange field and the reported postharvest losses. The present findings of the study clarified the process by which the physical flow of oranges move within the value-chain, the marketing alternatives to farmers, and constraints faced by primary actors in the chain.