We developed a sensitive and rapid loop-mediated isothermal amplification (LAMP) assay for detection of Campylobacter fetus. This assay provides simpler and more rapid detection of C. fetus than conventional biochemical and PCR assays. The assay correctly detected 60 C. fetus strains but not 55 non-fetusCampylobacter and 30 non-Campylobacter strains. The sensitivity of the LAMP assay in pure cultures and in a spiked bovine liver specimen was 10-fold more sensitive than that of the conventional PCR assay. The sensitivity of the LAMP assay in a spiked bovine vaginal mucus specimen was similar to that of the conventional PCR assay. The assay was markedly faster, requiring less than 40min for detection of C. fetus in a single colony on blood agar and 80min in spiked bovine specimens from the beginning of DNA extraction to final determination. Our LAMP assay is a simple and practical tool for detection of C. fetus regardless of subspecies.