The proximate and mineral constituents of six plantain forms, raw green plantain (RGP), cooked green plantain (CGP), raw ripe plantain (RRP), cooked ripe plantain (CRP), green plantain meal (GPM) and ripe plantain meal (RPM) were determined by chemical analysis. 24 large white barrows, weighing initially, between 40-45 kg., were used to study the apparent digestibility of nutrients, digestible energy (DE), metabolizable energy (ME), metabolizable energy corrected for nitrogen retention (ME(n) and total digestible nutrients when the plantains served as the only source of nutrients. In a second experiment ME and ME(n) were measured for the plantain forms using 28 Large White barrows, with diets in which the plantains replaced 50% of maize in a basal diet. All the plantain forms had low fat, crude fibre and crude protein content but high in nitrogen-free extract, phosphorus, potassium and Iron. Identically high dry matter (D.M.) and nitrogen-free extract (N.F.E.) digestion coefficients were obtained for all the plantain forms except RPM, which had significantly lower values. Digestion coefficients for crude protein (46.9, 53.6, 51.8, 34.3,-32.7 %), crude fibre, (46.6, 49.5, 58.7, 62.6, 56.9, 39.6 %), ether extract (55.9, 56.6, 66.9, 69.2, 54.7 and 34.6 %) for RGP, CGP, RRP, CRP, GPM and RPM respectively were considerably lower than for D.M. and N.F.E. The DE, ME ME(n) and TDN values were comparable for all plantain forms except RPM, which had significantly lower values in most cases. The fresh green plantains and green plantain meals had slightly higher energy values than the ripe plantains, even though the nutrients in the ripe plantains were better digested than in the green forms. The results are discussed in relation to variations in the relative proportions of the simple and more complex carbohydrates during ripening.