This paper studies jump flooding as an algorithmic paradigm in general-purpose computation with GPUs. As an example application of jump flooding, the paper discusses a constant time algorithm on GPU to compute an approximation to the Voronoi diagram of a given set of seeds in a 2D grid. The errors due to the differences between the approximation and the actual Voronoi diagram are hardly noticeable to the naked eye in all presented experiments. The same approach can also compute in constant time an approximation to the distance transform of a set of seeds in a 2D grid. In practice, such constant time algorithm is useful to many interactive applications involving, for example, rendering and image processing. Besides the experimental evidence, this paper also confirms quantitatively the effectiveness of jump flooding by analyzing the occurrences of errors. The analysis is a showcase of insights to the jump flooding paradigm, and may be of independent interests to other applications of jump flooding. (Jump Flooding in GPU with Applications to Voronoi Diagram and Distance Transform. Guodong Rong and Tiow-Seng Tan. To appear in 2006 SIGGRAPH Symposium on Interactive 3D Graphics and Games. [I3D 2006] )