The research aimed to identify the degree of fishermen's knowledge of fish handling and marketing in Lake Nasser in Aswan Governorate, and to identify the nature of the relationship between the degree of fishermen's knowledge of fish handling and marketing and the independent variables studied, and to identify the most important problems facing the respondent fishermen community related to fish trading and marketing in Lake Nasser. Research data was collected through a personal interview questionnaire for a regular random sample of 341 respondents, representing 11.3% of the total number of 3021 respondents, using the Cochrane equation. Frequencies, percentages, relative weight, and Spearman's rank correlation coefficient were used to analyze the data and present the results. The most important results were the following: It was found that 21.4% of the respondents fall into the low degree of total knowledge category in the field of fish handling and marketing. It was also found that 32.8% of the respondents fall into the medium-level category, while only 45.7% of them fall into the high-level category. Thus, more than half of the respondents, 54.2% fall into the low- and medium-level categories. It also became clear that the most important problems related to the circulation and marketing of fish are the high prices of fuel needed to operate fishing boats, which came in the first place with a relative weight of 100%.