This presentation will discuss variables in rodent colony management that can affect colony breeding efficiency, rodent health, and factors that can modulate rodent models of disease. Variables discussed will include housing and husbandry, environment and genetic background. Differences in husbandry that may impact research studies are varied and include environment (temperature, humidity), caging conditions (bedding, enrichment, or cage position), as well as animal husbandry staff. The genetics discussion will detail the importance of genetic background in scientific research, particularly as it relates to transgenic rodent colony management and breeding. Discussions will include awareness and management of potential research variables to minimize variation and optimize reproducibility in research. The participants will gain a broader understanding of these variables and how to use this information in different situations.