Following the isolation of Mycoplasma phocicerebrale from the flipper wound of a grey seal (Halichoerus grypus) in Cornwall, UK, surveillance for Mycoplasma species was extended to include other seals rescued or found dead around the UK. Mycoplasma phocicerebrale was frequently detected from the teeth of seals and from infected wounds and respiratory tracts. Mycoplasma phocirhinis, Mycoplasma phocidae, and some unidentified Mycoplasma species were also detected. Mycoplasma phocicerebrale and M. phocidae were the only bacteria consistently identified from the wound infections, but their role in respiratory and other diseases remains unknown, as other bacteria were also isolated from respiratory sites.