Disclosed is a composite focusing wedge for ultrasonic non-destructive testing/inspection. The composite wedge comprises a base made of machined or cast material, and a lens made of a material which is cast in liquid form and subsequently solidifies. The acoustic velocity in the base material is less than that in the lens material. The castable lens material conforms exactly to a convex machined or cast surface of the base, thereby forming a concave lower surface of the lens. A flat ultrasonic probe is coupled to a planar upper surface of the lens. The minimum distance between the lower concave and upper planar surfaces of the lens is less than one acoustic wavelength in the lens material. The ringdown time of reverberations between the two surfaces is then sufficiently short that there is no interference between the reverberations and signals from sub-surface flaws in the object being tested.