The law for handling and control of dogs in Berlin of September 29, 2004 was enacted to prevent the risks for humans and animals when ever they have contact with dogs. "Dangerous dogs" are defined by this law. There are 10 breeds of dogs supposed to be dangerous due to specific characteristics of their breed ("listed breeds"). The dangerousness of a dog's breed is not identical with the dangerousness of an individual dog. The subject of this study is to examine the potential dangerousness of dog breeds and not the individual dangerousness of a dog. This study refers to statistics of incidents between dogs and humans in Berlin for the years 1998 to 2004. The population density of a breed is based on the dogs assessed for tax purposes in Berlin of January 1, 2005 and on the dog registrations maintained at veterinary hospitals. The fourfold-table-test was used to compare the quantity of the recorded incidents of two statistically independent dog breeds. Of the total population of 107,804 tax assessed dogs in Berlin in 2004, 0.9% was documented as dogs involved in incidents with humans. The incidents per year decreased in the "listed breeds"about 68% and in the "unlisted breeds" about 41% during the last 7 years in Berlin. Therefore, the probability (the odds ratio) of a breed to be conspicuous was analysed. The values for the calculation of this probability were the number of dogs of a breed having been involved in incidents compared to the population of this breed based on tax records. The comparison of the probability of a breed with another to be conspicuous was used to compile a cluster of breeds which had the same probability to be conspicuous in 2004. A cluster was assessed for dogs of the following breeds: Sheep dogs, Rottweiler, Doberman, Pitbull Terrier and American Staffordshire Terrier. A listing of breeds is not the right way to reduce the potential dangerousness of a dog, especially in the private domain of their owners. Most incidents with dogs occur in the private domain which normally is not recorded in the statistics of incidents. Therefore, it is more effective to support activities which include the training of abilities of the dog owners. Training by experts can enable dog owners to avoid conflict situations with their dog, or in case of conflict, to take appropriate actions.