- Kleijnen Systematic Reviews Ltd is an organisational member of ISPOR, the International Society for Pharmacoeconomics and Outcomes Research: http://www.ispor.org/members/orgmember.asp
- Kleijnen Systematic Reviews Ltd collaborates with the Vienna School of Clinical Research: www.vscr.at
- Kleijnen Systematic Reviews Ltd collaborates with the Horten Centre: www.evimed.ch
- Kleijnen Systematic Reviews Ltd collaborates with Nixon Health Economics: http://www.nixon-he.co.uk
- Kleijnen Systematic Reviews Ltd is affiliated to the James Lind Alliance: www.lindalliance.org