The successful growth of 2-in. -Ga 2 O 3 crystals by the edge-defined, film fed growth (EFG) method was demonstrated. The optimization of growth conditions for larger single crystalline -Ga 2 O 3 is discussed in detail. The seeding conditions of temperature and neck width were found to be the most important factors to grow single crystals. X-ray rocking curve measurements of -Ga 2 O 3 crystals were conducted to estimate the dislocation densities of the grown crystals. Etch pit densities (EPDs) of the -Ga 2 O 3 crystals were also measured using KOH solution to measure the dislocation densities. The results were discussed combining with crystal growth parameters such as neck width to clarify the mechanisms of propagation and the origin of dislocations in crystals from phenomenological and crystallographic points of view.