Since the first cloned dog "Snuppy" was born, many cloned dogs have been produced by somatic cell nuclear transfer (SCNT) technology. We reported the production of seven cloned drug detection dogs (named "Toppies") in 2009. Although their genetic identity was confirmed, similarities in behavior and the drug-detecting ability were not examined. Therefore, this study is the first attempt to examine their behavior. We conducted the Campbell test which is commonly used to evaluate the tendency of dominance. Data were analyzed by the general linear mixed model. The scores among seven cloned puppies and four naturally-bred controls were significantly different (P < 0.0001). After the test, cloned and control puppies were trained according to the Korea Customs Detector Dog Training Center's manual. The selection rate for detector dog in the cloned puppies was higher (86 %) than that of naturally-bred dogs (30 %). Therefore, it can be concluded that drug detection dogs with high performance can be propagated more efficiently using SCNT.