The 17 August 1999 Kocaeli earthquake in Turkey produced a major surface rupture. We traced this surface rupture from Golcuk to Duzce and located it accurately by using GPS. The closest distance from the surface rupture to the strong motion observation sites were determined. Then the attenuation characteristics of the observed peak ground acceleration were compared with the attenuation relation given by Fukushima and Tanaka (1992), which is suitable for the near-fault zone in Japan and gives results that closely match data recorded during the 1995 Hyogo-ken Nanbu earthquake in Japan. Although this attenuation relation was developed for Japan, we found that it agreed well with the KOCAELI earthquake. Furthermore, the observed spectral acceleration of 5% damping was compared with the building design code of Turkey and the observed level was lower than the code.