Cobalt(III) is a component of cobalamin. Its essentiality as trace element results from the capacity of certain animal species to synthesise cobalamin by the gastrointestinal microbiota. Feeding supplemental cobalt from the additives under application up to the maximum total content in feed set in EU is considered safe for all animal species/categories; margin of safety is around 10. Cobalt is predominantly excreted via faecal route. Absorbed cobalt follows aqueous excretion routes. About 43% of body cobalt is stored in muscle; however, kidney and liver are the edible tissues containing the highest cobalt concentrations and are most susceptible reflecting dietary cobalt concentrations. In animals with capacity to synthesise cobalamin, cobalt is also deposited in tissues as vitamin B12. Cobalt(II) cations are genotoxic under in vitro and in vivo conditions, and have carcinogen, mutagen and reproduction toxicant (CMR) properties. No data are available on the potential carcinogenicity of cobalt(II) following oral exposure. However, oral exposure may potentially entail adverse threshold-related effects in humans. The estimated population intake of cobalt most likely includes the contribution of foodstuffs from animals fed cobalt-supplemented feedingstuffs. An increase in cobalt exposure by the use of cobalt-containing feed additives is therefore not expected. Considering the population exposure to cobalt, about 4–10 times lower than the health-based guidance value, no safety concern for the consumer is expected for threshold effects of oral cobalt. The cobalt(II) compounds assessed are considered skin and eye irritants and dermal/inhalatory sensitisers. Their dust is a hazard to persons handling these substances. Exposure by inhalation must be avoided. The use of cobalt from any source at the authorised maximum content in feed does not provide a risk to the environment. The compounds assessed are available for cobalamin synthesis in the rumen and therefore effective in ruminants; this conclusion is extrapolated to horses and rabbits.