This study attempts to investigate the industrial practices of the web site development methodologies and their impacts on the web site development project performance. Most of Korean web site development firms currently use customized component-based development(CBD) methodologies that have been internally developed. The methodologies generally being accepted by web site developers, however, did not emerge yet. In addition, this study shows that indiscreet applications of various methodologies and techniques might cause negative impacts on the project performance since the web site development projects are also exposed to most of the risk factors identified in the traditional systems development.