Mature and total TGF-β2 levels were determined in normal human tears, from 37 volunteers, using a quantitative‘sandwich’enzyme immunoassay technique. Since this ELISA method recognizes only mature TGF-β2, total TGF-β2 levels in tears were measured after acid activation. Aqueous humor samples from 9 patients with cataract were also tested as controls. Mature and total TGF-β2 in aqueous humor (AH) averaged 182 pg/ml and 737 pg/ml, respectively. The levels of mature TGF-β2 in normal human tears ranged from 36 to 71 pg/ml (mean: 55 pg/ml). And the levels of total TGF-β2 ranged from 3446 to 14910 pg/ml (mean: 7854 pg/ml), a very high level. Percentage of mature TGF-β2 ranged 0.4 to 1.3% (mean: 0.9%). It is reported for the first time that there are very high levels of total TGF-β2 in normal human tears. Curr. Eye Res. 15: 341–343, 1996.