**Abstract**

It is often advantageous to store collected environmental samples for future retrospective analyses. However, information about sample stability is necessary to determine if there will be analyte loss or gain or degradation under the specified storage conditions and storage period. Failure to evaluate stability could result in inaccurate results and biased exposure assessments. As part of the National Children's Study pilot, we considered which types of environmental samples could be stored for extended periods of time. We conducted an extensive literature review and considered the conduct of long-term stability studies for environmental samples. We present our findings and experience below as guidance for consideration by the environmental research community.

**Keywords:** Sample stability, Sample storage, Environmental samples, Long-term studies
