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Salmonella gallinarum with the biotypes gallinarum and pullorum causes two septicaemic diseases in poultry: fowl typhoid (FT) and pullorum disease. The former Salmonella pullorum serovar is not recognised anymore as such. Both biotypes are differentiated by a few biochemical and molecular tests. Mammals may be infected without showing any illness. In contrast to zoonotic salmonella serovars, Salmonella gallinarum does not cause any gastroenteric disease in humans transmitted throughout the food chain. Many animals, including men, may become asymptomatic carriers. Vectors such as rodents, flies, darkling beetles and red mites are very important reservoirs and sources of infection. Although FT has been officially eradicated from North America, Oceania, Japan and many European countries, infection may appear again because wild birds can harbour Salmonella gallinarum; this has been the case in the UK in 2006-20072011. FT subsists as an endemic infection in some countries from Central and South America, Africa, Middle East, and several CIS and Asian countries. In some commercial poultry operations Salmonella gallinarum is found but remains officially under reported, or in fact, the infection may be really unknown when outbreaks take place in backyard flocks. Birds become chronic carriers passing the disease to their offspring through eggs. Approximately one third of the eggs are contaminated. Cross contamination in the hatchery is crucial for spreading the disease. Horizontal transmission usually takes place orally although sometimes occurs by the respiratory route when dry manure is manipulated in the farm and the hen inhales the dust. Environmental contamination (for example feed, water and litter) and cannibalism are significant factors triggering the infection. It has to be taken into account that Salmonella gallinarum is able to survive in favourable environments or inside red mites for several months.