Activated protein C (APC) is an anticoagulant, which also exerts potent anti-inflammatory and cytoprotective effects. Microparticles (MP) are naturally occurring vesiculations that bud-off from cell membranes. Under pathological conditions the number of MP is greatly increased and they promote pro-inflammatory and pro-coagulant effects. The aims of this study were to determine whether APC i) regulates MP production, ii) regulates the presence of pro-inflammatory markers on the surface of MP, iii) is present on MP and iv) retains anticoagulant activity on MP. Immortalised human brain endothelial cells (HBECs) were cultured and treated with tumor necrosis factor (TNF) or interferon (IFN)γ in the presence or absence of recombinant human APC. MP from supernatants were isolated and analysed for annexin V binding to phosphatidylserine (for total MP), inter-cellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 via flow cytometry. The presence of APC on MP was detected using a chromogenic substrate based amidolytic activity assay. Prothrombin time (anticoagulant activity) of MP was measured using an automated coagulometer. APC did not stimulate MP production, unlike TNF, which significantly increased total (1.4 fold), ICAM-1 (2.3 fold) and VCAM-1 (6.6 fold) positive MP. IFNγ with or without APC had no significant effect on MP production. APC significantly decreased TNF-stimulated total MP by 38% (P ≤ 0.001). Cells treated with APC produced MP with significantly higher levels of amydolytic activity. Coagulation times using MP produced in the presence of APC were significantly higher (77.4 sec, P ≤ 0.001) than non-stimulated cells (20.9 sec) or in the absence of MP (21.5 sec), and confirmed with HUVECs. This work suggests that APC would reduce MP-associated pathologies by decreasing the number of MP.