Reducing yield gaps is one of the major pathways identified to meet the future food demand (Keating et al., 2014). A prerequisite to design strategies to reduce the yield gap of crops is to understand its causes. The sustainability of most vegetable farms in south Uruguay is threatened by low family income and deteriorating soil quality. The main cause of low income is that most farms obtain 50% or less of the attainable crop yields in the region, with similar production resources and proper management (Dogliotti et al., 2014). Low yields are the main cause of low labour productivity and resource use efficiency. There is a huge variability between farmers in crop yields, product quality and economic results. To explain the main causes of this variability and to identify strategies to reduce the distance between the average yield and the top yielding fields and farms, we started a project to study important vegetable crops in south Uruguay (onion, tomato, sweet potato and strawberry). In this paper we present the method developed to explain variability in physical and economic results, the main causes identified in the seasons studied on strawberry and onion,and discuss strategies to reduce the observed gaps.