- A3P Services
- Abaxis
- Abbott GmbH & Co. KG
- Abbott Laboratories
- Accelr8 Technology Corporation
- ACON Laboratories, Inc.
- AcroMetrix
- Adaltis Inc.
- Advanced Biotechnologies Inc.
- AdvanDx
- AES - Chemunex, Inc.
- AES Chemunex
- AES Chemunex Canada
- Affymetrix, Inc.
- AFNOR
- AHVLA Scientific
- AID GmbH
- Alere
- Alere, Inc
- ALP
- Alpha Laboratories Ltd
- American Association for Laboratory Accreditation (A2LA)
- Anachem Ltd
- Analytik Jena
- Ani Labsystems Ltd. Oy
- AOAC
- Applied Biosystems
- aqua-tools.com
- Argene SA
- Argonide Nanomaterials Corporation
- Artel
- Aseptika Ltd
- Associates of Cape Cod, Inc.
- Astell
- ASTM International
- Astra Biotech GmbH
- ASYS Hitech
- ATCC
- Atlantic Biologicals
- Autoscribe Ltd.
- Axis-Shield
- Azbil BioVigilant, Inc.