The concept of sustainability is one of the forefront issues in global agricultural production at present, given mounting pressure to increase food production in both a socially responsible and environmentally friendly way. From an Irish perspective the sustainable intensification of agriculture is of particular relevance given ambitious targets to increase milk production by 50 percent by 2020, in the context of European milk quota removal. Alongside this, environmental targets may be specified, meaning that expansion would have to be achieved in a sustainable way. To evaluate dairy farm-level sustainability a series of indicators are developed here using Teagasc National Farm Survey FADN (Farm Accountancy Data Network) data for Ireland from 2012. Three dimensions, reflecting the multifaceted nature of sustainability (economic, environmental and social) are considered. Given the environmental challenges inherent in the sustainable intensification of agriculture, it is encouraging to observe that the more intensive, top performing farms (in an economic sense) emit relatively less greenhouse gases when compared to their less intensive counterparts. Conversely, the better performing farms in economic terms tend to have higher nitrogen surplus per hectare on average. This is consistent with their higher rates of production intensity but poses a challenge in terms of sustainable expansion. That said this analysis demonstrates that the nitrogen use efficiency of milk production is positively correlated with economic performance, with more intensive farms producing relatively more milk per kg of nitrogen surplus. From a social perspective demography also tends to be correlated with economic performance. These indicators allow for the continued assessment of the sustainability status of Irish farming.