IgA nephropathy (IgAN, Berger’s disease) is a kidney disease characterized by the accumulation of immune complexes containing IgA1 in the glomerular mesangial areas. This IgA1 contains less galactose than IgA1 in the circulation and is termed galactose-deficient IgA1 (Gd-IgA1). The accumulation of the immune complexes culminates in glomerular injury, leading to hematuria, proteinuria, hypertension, and progressive decline in kidney function. Clinical presentation is variable, ranging from asymptomatic microscopic hematuria to rapidly progressive glomerulonephritis. Diagnosis is established by a pathological assessment of kidney biopsy with immunofluorescence microscopy showing IgA as the dominant or co-dominant immunoglobulin. Management includes supportive care with blood pressure control, reduction of proteinuria, and healthy life-style measures to slow progression of chronic kidney disease. Disease-targeting medications to slow the loss of kidney function and reduce proteinuria have recently become available, as have other agents to reduce proteinuria; clinical trials are ongoing to assess even more potential treatments.