The glomerular expression (mRNA levels) of transforming growth factor‐β1 (TGF‐β1) was assessed in two forms of rat anti‐glomerular basement membrane (GBM) disease, a macrophage‐independent and a macrophage‐de‐pendent variant. After a single intravenous injection of rabbit anti‐rat GBM immune serum, significant proteinuria and histopathologic changes developed in both variants. Increased TGF‐β1 mRNA levels were found in isolated glomeruli of the macrophage‐dependent variant only in which glomerular infiltration by macrophages also occurred. Macrophages isolated from glomeruli of animals with this variant demonstrated TGF‐β1 mRNA levels comparable to those found in glomeruli isolated at the same time point after injection of the anti‐GBM serum. The observations indicate that in anti‐GBM disease, enhanced glomerular TGF‐β1 expression occurs in the macrophage‐dependent variant and suggest that infiltrating macrophages account for this event.