Abstract: In the Red River Delta (RRD) of Vietnam, small-pumping systems are one of main systems for paddy irrigation. It is imperative to analyze the operation and maintenance performance of irrigation systems by using the input factors when applying pricing mechanisms in the irrigation sector in Vietnam. In this study, based on the data of 48 irrigation systems managed by teams under irrigation companies, the non-parametric program, Data Envelopment Analysis, was used to measure the technical efficiency and scale efficiency for small-pumping scale irrigation systems in the Red River Delta. The seven input factors were the annual direct and indirect labor, materials, electricity, recurrent maintenance, overhead, and depreciation cost, and an output factor was the paddy areas irrigated by the systems. The results demonstrated that the average technical efficiency scores under constant returns to scale and variable returns to scale were 0.924 and 0.946, respectively. Thus, the wasted inputs were suggested to be 7.6% and 5.4% of the current input level, respectively. The average scale efficiency score was 0.977 and therefore, some 72.9% of the Decision-Making Units should adjust their input scales to achieve the efficiency in input factors.