Agriculture played an important role in the organisation of economy and society in early medieval Ireland (cal ad 400–1150). This paper examines archaeobotanical evidence for agricultural production and consumption, incorporating newly available data. Analysis of evidence from 60 sites revealed that hulled barley and oat were the dominant crops of this period. Naked wheat was present at many sites, but was not the primary crop in most cases. Rye was a minor crop in all locations where recorded. Other crops—including flax, pea and bean—were occasionally present. These crop choices provide a contrast with evidence from many other regions in contemporary Europe. In the case of Ireland, there is increased evidence for crops during the second half of the early medieval period, both in terms of the number of sites where remains were recovered and also the variety of crops cultivated; this may reflect a shift towards a greater emphasis on arable agriculture. The contribution of documentary sources and scientific analyses towards investigating food products is also highlighted in this study.