In this decade there is a non linear growth in the data available on the World Wide Web, with this growth there arises a need for finding and analyzing useful data available on the web. The behavior of web page and how the users use the web can be found in the web log. The process of extracting knowledge from web log is called Web Log mining. This extracted knowledge can be used to enhance the quality of information being shared on the web. Web log are generally noisy and ambiguous, so data pre-processing is an very important step in Data mining. This project report gives overview on web log mining using decision tree, it provided privacy issues and a glimpse of various applications of web log mining.