Lifespan
In UK vet records the Labrador Retriever lives longer: a median of 13.1 years, against 11.7 for the Flat-Coated Retriever.
Shedding
Their coats shed differently: the Flat-Coated Retriever sheds through the year, the Labrador Retriever moults most as the seasons change.
Grooming
The Flat-Coated Retriever needs more grooming, brushing a few times a week, where the Labrador Retriever needs a brush once a week.
Temperament
They differ most on handler demand (Flat-Coated Retriever: needs steady training; Labrador Retriever: suits a first-time owner) and on sensitivity (Flat-Coated Retriever: average; Labrador Retriever: hardy, takes a busy home in its stride).
Alike
They are much the same size as adults, about 30 kg (66 lb) for the Flat-Coated Retriever and 31 kg (68 lb) for the Labrador Retriever.
Alike
Both are rated the same on affection: a lap or leaning dog.