We investigated 28 cases of bacteremia caused by Capnocytophaga species that occurred during an 8-year period, most of which were in patients with hematologic malignancy and neutropenia. Infections were uncomplicated, without serious organ involvement and without any apparent source except ulcerations of the oropharyngeal mucosa, and only 1 isolate showed resistance to beta-lactam antibiotics; 9 of 16 isolates were resistant to ciprofloxacin.