To achieve sustainability in the agricultural and rural sectors of the country, we are forced to reduce waste, increase the added value of products, and manage the resources and products of the sector. One of the most efficient tools to achieve this is the optimal use of the capacities of transformation and complementary industries in the agricultural and rural sectors. Theoretically, these industries are units that process and treat various agricultural products, including: crops, horticulture, livestock and poultry, forests, pastures, etc. The main objective of the present study was to determine the factors affecting the establishment of new processing and complementary industries units or the development of existing units in West Azerbaijan province. The present study is descriptive in terms of its applied purpose, descriptive in terms of data collection, and survey research in terms of its nature. The data collection tool and research information was a researcher-made questionnaire. The statistical population of the study included 51 owners of active processing and complementary industries units in West Azerbaijan province, and data were collected from them in the form of a complete count. Descriptive-inferential analysis of the data was performed using multiple regression analysis and SPSS software. The results showed that in terms of the ability to establish new units or develop existing units, the main focus should be on financial and economic variables.