A recent school of historical thought has emerged, centred around the writings of Maurice Bloch, which asserts that the imperial Merina economy from the early nineteenth century became totally dependent upon slave labour. It claims that there was such an influx of slaves into Imerina that slave numbers rose dramatically and all free Merina were relieved from productive work to engage in essentially non-productive occupations, notably the military, imperial administration and commerce. This article, which traces the development of forced labour in Madagascar and examines the structure of labour under autarky, takes issue with this viewpoint. It emphasises not only that the slave population of Imerina in the nineteenth century was lower than asserted, but that Bloch misunderstands the nature of fanompoana which, from the adoption of autarky in the mid-1820s, formed the organizing principle of most sectors of the imperial Merina economy outside subsistence agriculture. The impoverishment of the Merina economy which was a root cause of autarky led to a great decline in slave-holding amongst peasants who were in consequence largely obliged to work their own ricefields, either alone, or alongside the few slaves they managed to retain. By contrast, the Merina elite increasingly monopolized available labour resources, slave and fanompoana. Fanompoana, traditionally a limited form of prestation to the crown, was radically restructured under autarky between 1825 and 1861. Far from being ‘unproductive’, the imperial army, the largest fanompoana institution, constituted a huge and elaborate commercial organization which was used to exploit the empire's resources and channel them to the imperial heartland. At the same time, fanompoana units comprising Merina soldiers and colonists established farms and engaged in commerce in the provinces. Finally, fanompoana labour was widely used on the east coast plantations, and especially in the attempt to forge an industrial revolution in Imerina. In sum, this article argues that fanompoana rather than slavery formed the basis of the imperial Merina economy under autarky, ad was a major factor contributing to the failure of autarkic policies.