Instruct-NeRF2NeRF is an instruction-based editor for editing NeRF scenes. It uses an image-conditional diffusion model (InstructPix2Pix) to gradually edit the input image while optimizing the underlying scene, resulting in an optimized 3D scene that conforms to the editing instructions. We demonstrate that our method can edit large-scale real-world scenes and achieve more realistic and targeted edits than previous work.