Corynebacterium pseudodiphtheriticum is a coryneform and diphtheromorphic bacteria rarely found as a cause of pneumonia in immunocompetent hosts. A case of an immunocompetent patient with C. pseudodiphtheriticum pneumonia is presented. This infection responded well to initial empirical treatment with cefotaxime. Very few cases of pneumonia associated with C. pseudodiphtheriticum have been described in the medical literature, this organism mainly being found in immunocompromised hosts. We report a case of pneumonia in an immunocompetent patient in which C. pseudodiphtheriticum was the only micro-organism isolated.