We will present our recent work on III-V micro-cavity lasers monolithically grown on silicon substrates. The III-V material is directly grown using Template-Assisted-Selective-Epitaxy (TASE) within oxide cavities patterned using conventional lithographic techniques on top of the silicon substrate. This allows for the local integration of single-crystal III-V active gain material. Two variations of this technique will be discussed; the direct growth of disc lasers and the two-step approach via a virtual substrate. Room temperature single-mode optically pumped lasing is achieved in GaAs micro-cavity lasers, and devices show a remarkably low shift of the lasing threshold ( $ T_0 $ =170K) with temperature. Dependence on cavity geometry and pump power will be discussed.