P PT Krakatau Steel is a State-Owned Company specializing in the biggest steel industry in Indonesia. 1 n its manufacturing process, it produces exhausted gases such as S02. NO, and particulates. This research has an objective to learn the exhausted gases emission and dispersion of S02, N02 and particulates of Cold Rolling Mill. that is: to conduct quality observation and measurement on site air as well as to predict dispersion, the dispersion of pollutant gases of S02, N02 and particulates. theoretically using the Gaussian Model technique: (Snrmanlo lmamkhasani. 2002)The height of Cold Rolling Mill chimney-shaft is 22 m high and 2.3 m in diameter at the off gas speed (Vs) of 30 m/second and thus off gas debit (Q) is obtained 124.58 m2/second.Results of on-site measurement for SO2 that is point I at the distance 375 m,16.44 gg/m' Eastward: point 2 at distance 600 rn, 19.89.lg!m3. Westward; point 3 at distance 625 in, 19.89 ug/rn ' southwestward; point 4, 5 at distance I I 25 m; 1350 ; 3.51 I ug/m' southward and south-eastward for NOz that is point I, 2, 4 at distance 375 in; 600 m; 1125 m; 8.1 I I ug/rrr' East-, West-, and South-ward, meanwhile for point 3 at distance 625 rn, 12. 78.tg/m3 southwestward. and point 5 at distance I 350 m 26. 780 ug/rrr' south• eastward. Results of on-site measurement for S02 and N02 are still under the quality standard that is for SO~ 365 pg/rrr' and N02 150 µg/m3 meanwhile, on-site particulate measurement that four points are above the quality standard that is point 2 at distance 600 m 400 ug/rrr' westward, point 3 at distance 625 m 1969.9 µg/m southwestward and point 5 at distance 1350 m, 650,7 g/m3 south-eastward (quality standard according to PP 41I1999 of 230 ug/rn ') meanwhile for point I at distance 212 ug/rn ' eastward, still under the quality standard.Theoretical calculation results using Gaussian Model is obtained at the distance375 - 1350 m, then gas dispersion S02 is obtained ranging 2.39 x 10•10 - 5.42 ug/Nm'', N02 ranging 7.89 x 10•11 - 1.79 pg/Nrn ' and particulates ranging 2.93 x 10•11 - 0.67 ug/Nrrr', the results obtained are still under the quality standard.Theoretical calculation results in relation with statistical analvsis method in regression correlation that is for S02 R2 = 0.9595 and partikulate R2 = 'o.5314 may be interpreted that the on-site calculation may be influenced by the theoretical calculation, meanwhile, on-site N02 R2..,, 0.4412 on-site calculation is not influenced by theoretical calculation.