Updated project metadata. A20 is a negative regulator of NF-κB signaling, crucial to control inflammatory responses and ensure tissue homeostasis. A20 is thought to restrict NF-κB activation both by its ubiquitin-editing activity as by non-enzymatic activities. Besides its role in NF-κB signaling, A20 also acts as a protective factor inhibiting apoptosis and necroptosis. Because of the ability of A20 to both ubiquitinate and deubiquitinate substrates and its involvement in many cellular processes, we hypothesized that deletion of A20 might generally impact on protein levels, thereby disrupting cellular processes. We performed a differential proteomics study of bone marrow derived macrophages (BMDMs) from control and myeloid-specific A20 knockout mice, both in untreated conditions and after LPS and TNF treatment, and demonstrate proteome-wide changes in protein expression upon A20 deletion. Several inflammatory proteins are up-regulated in the absence of A20, even without an inflammatory stimulus. Depending on the treatment and the time, more proteins are regulated. Together these changes may affect multiple signaling pathways disturbing tissue homeostasis and inducing (autoimmune) inflammation, as suggested by genetic studies in patients.