Good optical quality single crystals of KBe2(BO3)F-2 (KBBF), an important new ultraviolet nonlinear optical crystal for phase-matching down to 177.3 nm, are grown from BeO-KBF4-B2O3 and KBBF-KF-B2O3 melts by spontaneous nucleation and top-seeded techniques. The effects of the solution compositions on crystal growth are investigated. The habit and defects of crystals are also discussed.