This paper examines the factors driving hidden underemployment on Irish farms during the course of the economic boom in Ireland and the subsequent economic decline post 2008. This measure of hidden underemployment is due to differences between the farmer‟s reported amount of labour and the standard labour requirement estimated in the Teagasc National Farm Survey. Hidden underemployment can be attributed to a number of factors relating to inadequate employment situations as described at the 16th International Conference of Labour Statisticians (16th ICLS) such as low productivity, casual work practices and the poor utilisation of skills and other factors specific to agriculture and/or self employment. We place particular attention upon the potential role of off-farm labour supply in solving the underemployment problem. We use a two-stage residual inclusion model and a random effects probit model to examine the forces behind farm underemployment. This paper provides an interesting set of results given that the end of the economic boom phase co-incided closely but not precisely with the decoupling of farm-level subsidies in 2006.