The invention relates to a joint prosthesis having a shaft made from a titanium alloy; according to the invention, it is provided that at least the shaft (10) is investment-cast and has a body-centered cubic crystal structure. A titanium alloy having this crystal structure (known as .beta.-titanium alloy) has an advantageously low modulus of elasticity which is well matched to the physiological demands. Furthermore, implementation as a shaped casting allows a complex shape to be achieved. It is particularly expediently embodied as a femoral prosthesis (1) for an artificial hip joint, which has an elongate shaft (10) with grooves (14) and sawtooth-like projections (15) for bone anchoring.