One of the agricultural commodities that have economic potential to be developed are the rice plants. The irrigation system of Subak Buaji, an area located in the outskirt of the city that have good potential and most commodities planted namely Commodity of Rice. The purpose of this study was to determine how much the productivity of rice farming, to determine the factors that affect the productivity of the production of rice farming, and to identify the constraints faced by farmers in Subak Buaji, Village of Kesiman Eastern Denpasar Sub-District. The choice of location was purposively and the selection of respondents was conducted by random sampling, the amount of respondents of the population that is descriptive (homogeneous) is at least 14% of the 147 population. Thus, the respondents were 30 people. The analytical method used in this research was the average variance and regression of Cobdouglas. The research results showed that the average cost per cropping season of rice farming was Rp 9,249,909 / ha, the average farm income per growing season was Rp.26,658,866 / ha, the average revenue per cropping season rice farming was Rp.17,515,049 and the average productivity of paddy per ha per season planting in Subak of Buaji was 5.21 tonnes / ha. The factors that most influenced on the productivity of rice farming was the use of inorganic fertilizers with a regression coefficient of 0.624, while the non-significant factor, namely the area of land with a regression coefficient of 0.695. The obstacles to productivity of rice farming, such as the technical aspects namely the aspects related to constraints experienced in the field such as, lack of availability of irrigation water, the lack of tractors in land culture, the higher number of land conversion and lack of capital to buy pesticides and fertilizers, socio-cultural aspects namely the lack of farmers' knowledge of the benefits of environmentally friendly fertilizer, the less attention to the best time for farming and the economic aspect was the lack of capital to finance production inputs such as pesticides financing. Farmers are advised to prefer inorganic fertilizers to increase productivity of rice farming to meet the recommendation of the local Agricultural Department, so that the nutrients in the soil is maintained. Furthermore, it can reduce the cost of buying chemical fertilizers.