Chronic kidney disease (CKD) is characterised by irreversible renal scarring. Nephrologists draw the distinction between primarily glomerular scarring (glomerulosclerosis) and scarring centred on the kidney tubules (chronic tubulointerstitial nephritis). However, in clinical practice, glomerulosclerosis is by far the most common pattern in CKD and this article will focus on this type of renal injury.