Lupus nephritis, a potentially devastating outcome of systemic lupus erythematosus (SLE), poses a real challenge in the management of SLE patients because of the difficulty in diagnosing its onset and identifying relapses before serious renal damage has ensued. Neutrophil gelatinase-B associated lipocalin (NGAL)/Lipocalin-2 has been implicated in the pathogenesis of several disease states in different organ systems, and especially in kidney diseases. Lipocalin-2 may play a protective role in the context of renal insults through the induction or prevention of apoptosis by an iron-transport dependent mechanism. Clinically, urinary Lipocalin-2 significantly correlates with measures of lupus nephritis disease activity, and may be an important and convenient marker for relapses.