Five cases of Pseudallescheria boydii infection are reported from the northern part of the United Kingdom. None of the patients had travelled abroad. Three cases of otitis in which P. boydii was associated with bacterial infections were diagnosed within a 6-month period. A lady who had diabetes mellitus presented with a pulmonary fungus ball in a pre-existent cavity caused by a previous bacterial infection. After minor trauma at the site of an old skin graft, a farmer's wife developed an ulcer on the dorsum of the right ankle. Precipitating antibodies were demonstrated except in two of the cases of ear infection. The management of the individual cases is discussed.