Today increasing productivity is the best and effective ways to achieve economic growth. The purpose of this study is analysis factors affecting labor productivity in producing major crops in central region of Mamasani Township in Fars province, Iran. The data of this study were collected by filling out questioners through interviews with 358 farmer of 24 Village of Mamasani Township in the year 1385-1386 (2006-2007) who were selected by stratified random sampling. Out of the factors that can affect labor productivity and were studied in this research are ages, sex, level of education, experience, farm size, participating in training extension programs, member of visits with extension men and access to credit. The analysis was done by using a multiple regression model. The results indicated that the level of education of read and write and primary, farm size degree of mechanization, membership in cooperative, participating in training extension programs by extension men and household – head residing in a highly developed village had positive and statistically significant effect on labor productivity. Variables such as level of education of high school Diploma, Experience, ratio of the amount of loan to current costs had negative and statistically significant effect on labor productivity. The results of this research suggest that enlargement of the size of farm, increasing the level of mechanization, extension and training program and farm visits by extension men be encouraged and facilitated by the authorities and policy makers.