Campylobacter lari is an organism occasionally isolated in humans but rarely causes bacteremia. We report the first case of cellulitis with bacteremia due to C. lari in a patient undergoing mantle-cell lymphoma. A 51-year-old man presented with a two-month history of fever and bilateral leg pain and redness. Despite oral ciprofloxacin administration, his symptoms had not improved. The blood culture sample in the anaerobic bottle yielded positive results and C. lari was identified by mass spectrometry. The bacteremia did not initially respond to oral azithromycin but responded to intravenous meropenem and amikacin for five days followed by oral minocycline. This report indicates that C. lari bacteremia may be treated with oral minocycline following short-term intravenous antimicrobial therapy even among patients undergoing hematological malignancies.