A household survey was conducted in An Giang province with 60 rice farmers to analyze the efficiency of fertilizer use in different crop seasons and production patterns. Research results show that there are two models of rice production including two crops per year (2C1Y) and three crops per year (3C1Y). In the 2C1Y model, the total amount of nitrogen (N), phosphorus (P2O5) and potassium (K2O) fertilizers applied by farmers are 133; 56 and 71 kg/ha/crop, respectively. Meanwhile, these nutrients in the 3C1Y model are 145; 81 and 79 kg/ha/crop, respectively. There is a difference in the efficiency of nitrogen and phosphorus uses between the two models. To produce one ton of rice, farmers use 18.1 kg of N in the 2C1Y model, but in the 3C1Y model, it takes 21.2 kg of N to produce one ton of rice. Similarly, phosphorous fertilizer use efficiency in the 2C1Y model is 7.6 kg of P2O5 and the 3C1Y model is 11.9 kg P2O5 per ton of rice. This result implies that the more intensive farming, the lower the efficiency of fertilizer use. On the other hand, the more intensive farming model, the more fertilizer used, the greater the impact on the environment. In the context of higher fertilizer prices and increasingly polluted environment, it is necessary to improve fertilizer use efficiency by reducing the level of farming intensification. Besides, other techniques like integrated nutrient management also should be studied.