A hollow poppet valve (31) is disclosed, in which a stem portion (13) includes a flared fillet portion (17), having a wall thickness (T), and a downwardly-extending cylindrical portion (33;51), having a cylindrical external surface (35). In the main embodiment, the valve includes a cap member (15) defining a seat face (25), and a cylindrical internal surface (39), the internal and external surfaces (39,35) being closely spaced apart, defining an interface having an axial length (L), and being consumed by a weld (43). Preferably, the length (L) of the weld (43) is equal to at least 1.1 times the thickness (T). The fillet portion (17) defines an internal fillet radius (R1), greater than 0.3 times the thickness (T), and near the radius (R1) is a transition region (TR). The present invention improves fatigue strength of the poppet valve by separating the transition region (TR) from the weld (43) so that there is overlap for no more than a minor portion of the weld.