Web usage mining deals with understanding the Visitor’s behaviour with a Website. It helps in understanding the concerns such as present and future probability of every website user, relationship between behaviour and website usability. It has different branches such as web content mining, web structure and web usage mining. The focus of this paper is on web mining usage patterns of an educational institution web log data. There are three types of web related log data namely web access log, error log and proxy log data. In this paper web access log data has been used as dataset because the web access log data is the typical source of navigational behaviour of the website visitor. The study of web server log analysis is helpful in applying the web mining techniques.