Background: Inflammatory cytokines dysregulate microvascular function, yet how cytokines affect lymphatic endothelial cells (LEC) are unclear. Methods and Results: We examined effects of TNF-α, IL-1β, and IFN-γ on LEC proliferation, endothelial cell adhesion molecule (ECAM) expression, capillary formation, and barrier changes in murine (SV-LEC) and human LECs (HMEC-1a). Results: All cytokines induced ICAM-1, VCAM-1, MAdCAM-1, and E-selectin in SV-LECs; TNF-α, IL-1β and IFN-γ induced ECAMs (but not MAdCAM-1) in HMEC-1a. IL-1β increased, while IFN-γ and TNF-α reduced SV-LEC proliferation. While TNF-α induced, IFN-γ decreased, and IL-1β did not show any effect on HMEC-1a proliferation. TNF-α, IL-1β, and IFN-γ each reduced capillary formation in SV-LEC and in HMEC-1a. TNF-α and IL-1β reduced barrier in SV-LEC and HMEC-1a; IFN-γ did not affect SV-LEC barrier, but enhanced HMEC-1a barrier. Inflammatory cytokines alter LEC growth, activation and barrier function in vitro and may disturb lymphatic clearance increasing tissue edema in vivo. Conclusion: Therapies that maintain or restore lymphatic function (including cytokines blockade), may represent important strategies for limiting inflammation.