The National Seed Health System (NSHS) is a program authorized by USDA-APHIS and administered by the Iowa State University Seed Science Center to accredit both private and public entities to perform certain activites needed to support the issuance of Federal phytosanitary certificates for the international movement of seed.

Activities for which entities can obtain accreditation include

• Laboratory seed health testing: laboratory-based program to test for plant pathogens in seeds,
• Phytosanitary (growing season field) inspection: disease inspection of plants grown to produce seed in the field, nursery, or greenhouse
• Seed sampling: sampling seeds that requires laboratory seed health testing
• Visual inspection: visual inspection of seed shipments at exporter's facility prior to issuance of phytosanitary certificates

Through the NSHS, new testing and diagnostic methods are incorporated into the accreditation program to maintain the program on the cutting edge of technology. The NSHS also serves as a resource for pest risk assessment and phytosanitary resolution whenever disputes arise that disrupt the international movement of seed.