Vegetable production constitutes an important sub-sector of the agricultural economy of KwaZulu-Natal. Most vegetables are cultivated in mixed-cropping types of farming systems. The technical efficiency of vegetable based cropping systems was estimated in order to identify the potential increase in production without incurring additional costs. The factors affecting technical efficiency and constraints and potential of the cropping system were also investigated. A field survey was conducted covering 120 vegetable farmers in the irrigated Tugela Ferry scheme and dryland farming sector in Msinga district during October to December 2003. According to a stochastic frontier production function using a Cobb-Douglas model, hired labour, organic fertilizer, inorganic fertilizer, area harvested and soil fertility maintenance cost showed significant positive effects on vegetable production. The mean technical efficiency of the vegetable based cropping systems was 84.32%. According to the inefficiency model the efficiency increased significantly as a result of farm visits by extension officers, participation in farmer training, less sloping lands, more experience, and higher diversity of the vegetable system. Technical efficiency decreased, however, with higher education level of the farmer and with higher off-farm income. Farm income is low due to low productivity, market constraints, lack of technology, and institutionally related constraints. Environmental conditions in the Msinga district are such that a high value crops can be grown with an adequate supply of irrigation water. There is a good possibility for stepping up production of these crops in marginal lands through appropriate crop diversification.