The six identical steam generator units for the 300-MW(e) Thorium High-Temperature Reactor in Germany deliver both main and reheat steam at conditions similar to fossil-fired plants. Typical design characteristics are the once-through principle and the helical tube arrangement. Combining this with downhill boiling results in a simple design. Materials have been selected considering operation, fabrication, and conformity with codes of different countries. Some special manufacturing operations are the automated welding techniques, coiling and bending, forging, and the extensive quality control effort. The techniques developed can be applied to future plants without excessive modifications.