The present invention provides cross-species anti-latent TGF-beta 1 antibodies. The present inventors have conducted diligent studies and consequently created cross-species anti-latent TGF-beta 1 antibodies which inhibit a protease mediated activation of TGF-beta 1 but do not inhibit integrin mediated activation of latent TGF-beta 1. It has been reported that latent TGF-beta is cleaved to release active TGF-beta by proteases. However, surprisingly, the present inventors have found that the anti-TGF-beta 1 antibodies inhibit a protease mediated activation of latent TGF-beta 1 without inhibiting protease mediated cleavage of the LAP region of latent TGF-beta 1, and have in vivo anti-fibrotic effects as well. Further, antibodies of the invention are useful for the diagnosis or treatment of cancer, and can also be used in combination with immune check point inhibitors.