The Munchkin is the founding breed of chondrodysplastic (short-legged) dwarf cat. Through outcrossing the Munchkin with a variety of normally proportioned cats a substantial number of dwarf breeds have been developed.
The major dwarf breeds as set out on the Dwarf Cat Association's website are as follows:
- Bambino - A cross between a Munchkin and a Sphynx cat
- Dwelf - A cross between a Munchkin and an American Curl
- Napoleon - A cross between a Munchkin and Persian cat
- Skookum - A cross between the Munchkin and LaPerm cat 
- Kinkalow - A cross between the Munchkin and the American Curl
- Lambkin - A cross between a Munchkin and Selkirk Rex
- Genetta - A cross between Munchkin, Bengal cat, Savannah cat , Domestic Short Hair cat and Oriental SH - exotic, spotted/marbled cat like a wild African Genet.
- Minskin - A cross between Munchkin and Shynx cat, Devon Rex cat and Burmese cat
The development of dwarf cats is at a fairly early stage (since the mid 1980s) and dwarf cat breeders are striving for recognition with the major cat registries. They are not widely accepted outside of the USA. They are potentially banned under the European Convention for the Protection of Pet Animals (European legislation) and have been condemned in the British Magazine Cat World.
For example, an insight into registration problems  can be seen in respect of the Skookum as recited by the founder of this breed Roy Galusha.
In addition to chondrodysplastic dwarf cats, there are a number of normally proportioned dwarfed breeds. These are usually termed "mini-" or "teacup" to differentiate them from the short-legged dwarf cats. Some may be due to a condition similar to primordial dwarfism found in humans. There are several lines of Teacup and Toy Persians currently bred, with some due to a spontaneous mutation and others due to consistently selecting and breeding the smallest individuals from each generation to progressively downsize the breed.
Another "dwarf" cat, also known as the "teacup cat", is a cat born with one of a number of mutations that cause the cat to be proportionally small rather than just short-legged. Although no single gene is involved and the cause of the dwarfism may be harmful to health, "teacup" cats have increased dramatically in popularity. Guinness World Records has a category for "Smallest Cat" which may contribute to the desire to breed ever-smaller cats from cats with potential genetic and health issues.
"Teacup" cats cause controversy in the cat fancy with many breeders considering them scams. Some may be runts born too early, or have nutritional deficits during kittenhood leading to retarded growth. When buying "teacups" of any animal it is necessary to exercise caution as primordial dwarf cats may have a number of health problems. Undersized cats also result from mutations such as types of mucopolysaccharides or other metabolic disorders.
As there are many different genes that retard growth, and as small stature may be due to non-genetic causes or to "teacup" cats coming from kitten mills, it is unsafe to generalize on health issues. Less scrupulous breeders may mistake serious metabolic disorrders as dwarfism. While some "teacup" cats do not show health problems, the health problems that have been reported in others include:
- Severe growth retardation causing bones to become misshapen and soft.
- Slowing rate of muscle mass growth. Causing weakness and a possibility of decreased use of limbs.
- Heart murmurs and enlarged heart.
- Seizures and other neurological problems, possibly causing blindness.
- Soft spot in top of skull, leaving cat susceptible to major head trauma.
- Misshapen jaw and bowed legs.
- Shortened lifespans
- Undeveloped or malformed reproductive organs