Variation in milk production is depended on different factors including: temperature, humidity and day length, which are changing at different months of year (Saremi et al., 2003, Naerian et al., 2003). Dairy industry sustain loss or make profit according to amount of milk production or ingredients during year (Barbano et al., 1991). Traditional Bazaar and dairy industry are influenced by milk processing technology so that increased shelf time of products and whole milk and its products having the opportunity to distribute more effective (Erba et al., 1996). Seasonal changes in milk production leads to more processing of milk and changes in total solids of milk, which can influence price of milk (Stephenson et al., 1989). This study designed to investigate seasonal changes in milk production and its fat content in addition to investigating these changes between years (1988-2003).