Background. The characteristics of acid soil, often low pH and high toxicity, affect the growth and yield of plants. Aims. This study evaluates the effects of supplemented lime and microbial organic fertilizer on glutinous corn (Zea mays) and watermelon (Citrullus lanatus) yield, yield components, and economic efficiency on acid-sulfate soils. Materials and Methods. Two experiments were carried out in Phung Hiep District, Hau Giang Province, as a typical acid-sulfate soil area. The randomized complete block with four treatments and three replicates was designed for the experiment, in which supplemented fertilizers were 800 kg of lime/ha; 2,000 kg of microbial organic fertilizer/ha; and 800 kg of lime in combination with 2,000 kg of microbial organic fertilizer/ha, and treatment as farmer dose (FFT), without lime and microbial organic fertilizer. Results. As a result, using lime combined with microbial organic fertilizer increased the yield compared to using only lime or microbial organic fertilizer. Besides, the incomes increased to 12.0% and 13.8%, respectively, compared to farmer recommendations. Conclusion. To improve the yield of glutinous corn or watermelon and income on acid-sulfate soils, lime should be applied at 800 kg combined with 2,000 kg of microbial organic fertilizer/ha.