[2] The coat is tan on the head and dark steel-grey on the body; no other colour is accepted by either The Kennel Club or the Fédération Cynologique Internationale.

In the mid-nineteenth century, workers from Scotland came to Yorkshire in search of work and brought with them several varieties of terrier dogs.

Hugh Dalziel, writing in 1878, says that "the classification of these dogs at shows and in the Kennel Club Stud Book is confusing and absurd" in lumping together these different types.

[2] For adult Yorkshire Terriers, The American Kennel Club places importance on coat colour, quality, and texture.

[2] The typical fine, straight, and silky Yorkshire Terrier coat has also been listed by many popular dog information websites as being hypoallergenic.

[27][28] The standard prescribes clearly defined fur-colours, and non-standard colours may indicate crossbreeding with other breeds or in rare cases even health problems.

Even though off-coloured Yorkshire Terriers are advertised at premium prices, being of an unusual or atypical colour is stated to be neither new, desirable, nor exotic.

For shows, the coat is left long, and may be trimmed to floor length to give ease of movement and a neater appearance.

The oil has to be washed out once a month and the wraps must be fixed periodically during the week to prevent them from sliding down and breaking the hair.

[33] The ideal Yorkshire Terrier character or "personality" has been described by the Kennel Club as having a "carriage very upright conveying an important air".

[34] Health issues often seen in the Yorkshire Terrier include bronchitis, lymphangiectasia, portosystemic shunt, cataracts, and keratitis sicca.

[35] Additionally, Yorkies often have a delicate digestive system, with vomiting or diarrhoea resulting from consumption of foods outside of a regular diet.

A 2013 study in the UK of patient records found the breed to have a life expectancy of 13 years, higher than the average.

[38] A 2024 UK study found a life expectancy of 13.3 years for the breed compared to an average of 12.7 for purebreeds and 12 for crossbreeds.

[42] Health conditions that can be found in Yorkshire Terriers, include distichiasis, hydrocephalus, hypoplasia of dens, Legg–Calvé–Perthes syndrome, luxating patella, portosystemic shunt, retinal dysplasia, and bladder stones.

[43] The following are other health conditions that affect the breed: A UK study found the Yorkshire Terrier to be 6.79 times more likely to acquire impaired hepatic perfusion compared to other dogs.

[54] Low blood sugar in puppies, or transient juvenile hypoglycaemia, is caused by fasting (too much time between meals).

[55] Very tiny Yorkie puppies are especially predisposed to hypoglycaemia because a lack of muscle mass makes it difficult to store glucose and regulate blood sugar.

[55] Factors such as stress, fatigue, a cold environment, poor nutrition, and a change in diet or feeding schedule may bring on hypoglycaemia.

Additionally, a hypoglycaemic Yorkie may have a lower than normal body temperature and, in extreme cases, may have a seizure or go into a coma.

[61] Opposition to this practice began very early in the history of the breed; Hugh Dalziel, writing about Yorkshire Terriers in 1878, declared that "There is no reason for mutilating pet dogs, and perfect ears and tails should be bred, not clipped into shape with scissors.

"[9] AKC and Canadian Kennel Club still require the Yorkie's tail be docked in order to compete at its events.