In an environment of low returns to agricultural activities and slow structural change, both employment and enterprise diversification have been presented as possible strategies for raising the incomes of farm households. This paper focuses on the barriers to taking up off-farm employment and establishing new non-agricultural enterprises. Factor and cluster analysis are applied to a data-set of individual farms in Poland in order to identify groups of households facing similar constraints and profile policy measures that are most likely to assist diversification. The majority of non-diversifiers are unlikely to become pluriactive in the near future due to a combination of age, a desire to concentrate on farming and remoteness. Farm households that are willing to diversify are characterised by the lowest agricultural incomes. For these households, a poor endowment of human and physical capital is a major constraint.