We prepared rod-shaped gold nanorattles-solid gold nanorods surrounded by a thin gold shell-using a galvanic replacement process starting with silver-coated gold nanorods. These structures are very promising candidates for catalytic applications and optimized plasmon sensors. They combine the advantages of rods (low plasmon resonance frequency, large polarizability, small damping) with the high surface area of hollow structures. The plasmon sensitivity to changes in the dielectric environment is up to 50% higher for gold nanorattles compared to gold nanorods with the same resonance frequency and 6 x higher than for plasmons in spherical gold nanoparticles. The catalytic activity measured for the reduction of p-nitrophenol is 4x larger than for bare gold nanorods.