Ti-based bulk metallic glasses (BMGs) developed in the past decade have been reviewed in terms of their compositions, glass-forming abilities and mechanical properties. The cast defects in the BMG samples, which significantly deteriorate the mechanical properties, are discussed and summarized based on the experimental results in the literature. Some results on the cast nanostructured Ti alloys with dendritic ductile beta phase are also reviewed. A special composite microstructure, dendritic beta-Ti(M) (in micrometer size) + rod-like eutectic beta-Ti/gamma-TiCu (in nanometer size), has been obtained in the as-cast cylinders smaller than 5 mm in diameter in the Ti-Cu-Ni-Sn-Ta(Nb) systems. The Ti alloys with such composite microstructure exhibit very high strength and remarkable plasticity.