I think the fastest dog ever recorded was a greyhound name Star something or maybe something Star? I think the dog ran like 41. something, almost 42 mph. The only reason I know that is because I took Drake out to Purina Farms when they had an event you could take your dog to see what they exceled and what they liked to do. It's a pretty cool event where they set up every dog sport you can think of and owners let their dog go for it. We tried most of them, mostly for s&g's but the running sports is where he exceled. I think it was lure corsing where one of the instrutors said that she thought he could break some records. That's when she told me about the greyhound. Of course a dog could be faster but that was the fasted offical speed.