InstaFlow is an ultra-fast, one-step image generator that overcomes computational constraints of diffusion models in text-to-image generation. It achieves image quality similar to Stable Diffusion but requires significantly lesser computational resources due to the use of a Rectified Flow technique. This technique enables training of probability flows with straight trajectories, requiring just a single step for quick inference. InstaFlow's advantages include ultra-fast inference, up to 90% faster than Stable Diffusion, high-quality image generation, and a simple and efficient training process. It produces results equivalent to top text-to-image GANs, like StyleGAN-T, and with the help of a pre-trained Stable Diffusion model, InstaFlow-0.9B requires only 199 A100 GPU days to train.