At present, there are no effective antiviral treatments available for contagious ecthyma, and rapid diagnosis is therefore critical for effective control of the disease. Recently, the invention of a novel LAMP technique that can rapidly amplify nucleic acids with high specificity and sensitivity under isothermal conditions has overcome some of the deficiencies of nucleic acid-based diagnostic tests and has made on-site diagnosis possible. To establish a flexible loop-mediated isothermal amplification (LAMP) assay for the rapid detection of orf virus, two pairs of primers, including outer primers F3/B3 and inner primers FIP/BIP, were designed to amplify the DNA polymerase gene. Optimal time and temperature conditions for LAMP were found to be 45 min and 62 °C, respectively. The LAMP assay was shown to be specific, with no cross-reactivity with sheeppox virus, goatpox virus, avian molluscum roup virus or vesicular stomatitis virus. Additionally, the sensitivity of the LAMP method was similar to that of real-time PCR and demonstrated greater sensitivity than a conventional polymerase chain reaction (PCR) assay. To assess the utility of LAMP in the detection of orf virus in clinical samples, a total of 35 samples collected from orf virus-infected sheep and goats were tested using the optimized LAMP assay, real-time PCR, and conventional PCR. Of the samples, 26 were found to be positive by LAMP, and 25 (74.3 %) were positive by real-time PCR, whereas only 18 (51.4 %) were positive by conventional PCR. Our results have shown that the LAMP assay developed in this study can be used for the rapid detection of orf virus.