In South Africa , De Beers employed Bullmastiffs as guard dogs at their diamond mines between 1928 and 1940. The dogs acquired and bred by De Beers formed the basis of the breed in South Africa.

The Bullmastiff Club of Southern Africa was founded in 1954 in Johannesburg and was affiliated to the Kennel Union of South Africa in 1955. Today it boasts a membership of 200 families and approximately nearly 600 Bullmastiffs are registered annually.
The modern Bullmastiff in South Africa is utilised mostly as a family companion and protector who is loved and appreciated for his loyalty and trustworthy temper.
As stated by one of the very first breeders of Bullmastiffs in Britain in the 1920s, Bullmastiffs were, and still are,

"Faithful and Fearless, but not Ferocious"