The attenuation of coda waves in the earth's crust in southwest (SW) Anatolia is estimated by using the coda wave method, which is based on the decrease of coda wave amplitude in time and distance. A total of 159 earthquakes were recorded between 1997 and 2010 by 11 stations belonging to the KOERI array. The coda quality factor Q (c) is determined from the properties of scattered coda waves in a heterogeneous medium. Firstly, the quality factor Q (0) (the value of Q (c) at 1 Hz.) and its frequency dependency eta are determined from this method depending on the attenuation properties of scattered coda waves for frequencies of 1.5, 3.0, 6.0, 8.0, 12 and 20 Hz. Secondly, the attenuation coefficients (delta) are estimated. The shape of the curve is controlled by the scattering and attenuation in the crustal volume sampled by the coda waves. The average Q (c) values vary from 110 +/- A 15 to 1,436 +/- A 202 for the frequencies above. The Q (0) and eta values vary from 63 +/- A 7 to 95 +/- A 10 and from 0.87 +/- A 0.03 to 1.04 +/- A 0.09, respectively, for SW Anatolia. In this region, the average coda Q-f relation is described by Q (c) = (78 +/- A 9)f (0.98 +/- 0.07) and delta = 0.012 km(-1). The low Q (0) and high eta are consistent with a region characterized by high tectonic activity. The Q (c) values were correlated with the tectonic pattern in SW Anatolia.