The laboratory rat is obviously an important model for physiology, pathology, pharmacology, toxicology, and transplantation experiments. The value for pharmacological research is immense since virtually every drug approved for human treatment passes through the body of laboratory rats. Hundreds of unique rat models have been developed to mimic pathological and physiological human clinical conditions, especially in the case of complex diseases. Many of the model rats are deposited into rat resource centers, from which researchers can use and share animals and rat related resources in biomedical research. Recent progressing technologies for genetically engineered rats, such as traditional transgenesis, chemical ENU mutagenesis, and transposon insertional mutagenesis, will provide thousands of useful rat models for functional genomics and human diseases. Globally acting rat resource centers are prerequisites for successful and sustainable research in the biomedical field where the rats are used as model species.