Fine-grained metals have attracted much interest due to the possibility to obtain both high strength and high ductility. Studies of the deformation mechanisms in fine-grained metals are therefore important, and can also help fill a gap in knowledge between nano-grained metals and conventional coarse-grained metals, which is an area of both scientific and industrial interest. For such an investigation it is very important to use a starting material with a simple microstructure. For this purpose spark plasma sintering (SPS) has been used to prepare samples of fully dense, fine-grained Al with average grain sizes ranging from 0.8 μm to 5.2 μm, in a fully recrystallized condition, with equiaxed grains and a random texture. The microstructures and mechanical properties of these sintered fine-grained Al samples have been studied using EBSD, TEM and compression testing. Based on these studies, relationships between the microstructure and mechanical properties have been established. The results show that the formation of deformation microstructure depends on grain size. During deformation, all grains in samples with an average grain size of 5.2 μm show grain subdivision by dislocation boundary formation, though few grains in a sample with an average grain size of 0.8 μm show dislocation boundary formation. The mechanical properties of fine-grained Al show a transition in behavior with decreasing average grain size. For samples with an average grain size of 1.3 μm, stress-strain curves show yield drop phenomenon, attributed to source-limited hardening. For a sample with an average grain size of 0.8 μm, the stress-strain curveshows only limited work-hardening after yielding, in agreement with the observation of the limited formation of dislocation boundaries inside grains during deformation. For a sample with average grain size of 5.2 μm the average dislocation boundary misorientation angle increases more quickly than in deformed conventional coarse-grained Al deformed to the same strain, due to the effect of increased volume fraction of grain boundaries and oxide particles. The strength of the SPS-prepared Al samples is higher than found for samples with identical grain sizes prepared by thermo-mechanical deformation, due to the presence of oxide particles, and to source-limited hardening for samples with average grain sizes smaller than 1.3 μm.