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