Plum is an important stone fruit of Pakistan after peach. It is prone to post harvest losses at different levels during its production and consumption. Evaluating post harvest losses in the marketing channel of the plum was necessary for the stake holders to make informed decision about harvest and post harvest practices. This study was conducted in Swat district in 2012 to quantify these losses at different levels using four different questionnaires. Proportionate stratified random sampling technique was used for the collection of data from different categories of respondents and tehsils. Post harvest losses were estimated through percentage method. The most important reasons were poor harvesting methods, over maturity, insufficient cold storage facility, poor grading, low-quality packaging materials and poor infrastructure. Total post harvest losses in the marketing channel of the plum were 21.51% of which 5.12% occurred at farm level, 1.44% at wholesale level, 6.31% at retail level, and 8.64% at the consumer level. Harvesting at proper maturity, using experienced labor and storage facility can reduce extent of post harvest losses of plum.