Agricultural development in Rwanda like in other developing countries faces numerous challenges and constraints related to persistent food insecurity, food price volatility; food safety, climate change and sustainability concerns. On the other hand, NGOs are mostly seen as a catalyst for societal change since they are responsive to the needs and problems of their clients, usually the poor, women and children and other group of people considered as the projects beneficiaries. This research discusses the main interventions of the NGOs and their contribution towards development of agricultural and food marketing among cooperative unions in Rwanda. The focus is to portray and analyse the interventions of non-profit making organisations and their contribution towards development of agricultural and food marketing among cooperative unions in Rwamagana district, in the Republic of Rwanda. In this research, quantitative and qualitative methods were used to collect qualitative information and to transform the collected data into numbers, measurements, statistics and numerical figures. A survey of 374 respondents comprising of farmers mostly involved in agricultural production, processing and food marketing activities in their cooperatives was performed. The research findings reveal that the NGOs have contributed to the expansion of cooperatives unions through the use of provided agricultural and food marketing development packages. These expected cooperative unions outcomes were like improving agricultural and marketing performance, acquiring customers’ information, building long-term relationship with customers and formatting strong relationships with a number of organisations in agricultural and food markets or wider marketing system. As a result, there is a noticeable progress towards cooperative unions’ performance. The cooperative unions improved their processing technology and a number of product ideas have been made possible through technological assistance. The adoption of advanced technology is still at early stage, but the cooperative unions’ members expect a number of improvements in terms of quantity and good quality products and hence the satisfaction of customers and increase of performance. In terms of performance, cooperative unions realized the above average performance in both financials and operations such as the total sales growth, the customer satisfaction, the cooperative unions’ market share, and the cooperative unions gain in market share and the overall cooperative unions’ success.