The dogs are rapidly increasing in popularity among those interested in a compact dog with a strong work ethic. They are especially popular in dog agility, and do well in other dog sports including herding, obedience, disc dog, and many other activities.
Miniature Aussies ranges in height from 13 to 18 inches (35 to 46 cm) at the withers and weighs between 17 and 40 pounds (9 to 18 kg). Coat colors are the same as those for Australian Shepherds, which are blue merle, red merle, black tricolor, red tricolor, black bicolor, and red bicolor. There is even a very rare type of coat color: Brown & white. The eye colors may vary; dogs may have two green eyes, one green & one blue, a blue& a brown, two browns, or two icy blue eyes. Even a green eye & a brown one is possible. With an Aussie anything is possible!
Miniature Australian Shepherds are eager to work, which makes training and interacting with them a pleasure, but their intelligence and drive require obedience training and plenty of interesting activity. Mini Aussie's are versatile and easily trained. Because they are herding dogs, they make good guard dogs and excellent companion dogs for those who provide an adequate outlet for the mini Aussie's physical and mental energy. Aussies provide playful companions for young children, though should be watched until you are sure the two get along well. Sometimes gets rough, but if you handle the puppy correctly he/she shall become a good full-grown dog. Miniature Australian Shepherds are purebreds, as some people may not think. They are NOT a breed of dog that came from Australian Shepherds and a smaller dog; farmers wanted a smaller herding dog (Aussies are still today used for herding ducks, sheep, cattle, etc...), so they bred the smallest STANDARD Aussies, and viola; came up with the mini aussie! They are very energetic dogs and therefore aren't good for families who will chain them up all day. They need to run they need to run they need to play they need to RUN they need to...sleep. if you leave them alone all day they will become neurotic and bored and may chew up. Some Aussies (like mine) may have separation anxiety. While you are gone (if your dog is in the house) call and leave a message. The dog may be comforted by your voice and may or may not disrupt anything. With an Aussie that has separation anxiety, I advise you to put away any expensive shoes behind locked doors or any other special things because they may be destructive. Always leave a few Kong toys stuffed with treats or food with them. Aussies are so smart they may get the food out in a few minutes, but it gives them something to do.
The history of the miniature Australian Shepherd is the same as that of the Australian Shepherd until approximately the 1960s. Thereafter, fanciers formed member clubs and registries to promote the smaller dogs in particular. While there were at one point in the past a few enthusiasts who wanted to pursue recognition as a separate breed, the fancy as a whole and the clubs that focus on the smaller sized Aussies consider the dogs merely a size variety of the Australian Shepherd. The parent clubs of the Australian Shepherd however do not recognize a size variety of the Australian Shepherd.
Miniature Australian Shepherds can be registered with the National Stock Dog Registry (NSDR), MASCA, NAMASCUSA and a variety of other registries.
Recent studies suggest that Miniature Australian Shepherds are more likely than their full-sized counterparts to carry the mutated MDR1 gene. Read here for more information about the dangers and risk of death caused by MDR1 mutation. 
The breed has shrunk even further to the smaller versions. The Toy Australian Shepherds are sized down to 13 or under. These smaller dogs are still energetic, and intelligent.