In most Welfare States, for most citizens of working age, access to a minimum income is typically conditional on employment-related activity such as job search, training or work itself. This chapter explores a case for unconditional minimum income (UMI). It discusses the possible justifications for conditionality. Conditionality in the income support system is presented as a means of ensuring that citizens do not enjoy income support on terms that violate the reciprocity principle. The chapter elaborates the fairness argument for conditionality that focuses on the principle of reciprocity: that those who choose to share in the benefits created by others' productive efforts should make a reciprocal effort in return. It indicates how this principle, far from being a 'neo-liberal' idea, is deeply rooted in egalitarian traditions of political thought and how making a minimum income conditional on work is also a common-place within this tradition. The chapter also situates the reciprocity principle within a wider discussion of economic fairness.