A furnace for growing single crystals of metals and metal alloys by the floating zone technique has been constructed. This makes it possible to grow single crystals of materials with a phase transition in their high temperature phase in situ on a neutron scattering instrument. Without the crystals being cooled below their transition temperature they can be oriented and a neutron scattering experiment can be performed. The typical crystal size is about 5 cm 3. The furnace is designed for continuous operation up to 2000 K under ultrahigh vacuum or high purity gas atmospheres. It gives access to a 360° neutron scattering plane with a maximum angle of inclination of ±20°.