Performance improvement of existing irrigation projects has been a major concern in international irrigation development. Activities for irrigation project improvement usually involve not only infrastructure (hardware) improvement but also changes in management. However, the impact of management improvement on irrigation performance has not been sufficiently verified because, in most cases, (a) irrigation project evaluation is done qualitatively, and (b) management improvement is implemented simultaneously with hardware improvement. Therefore, the impact of management improvement needs to be evaluated quantitatively and separately from hardware. This research attempts to quantify effects of management and hardware improvements on irrigation project performance, using the Analytic Hierarchy Process (AHP). First, an AHP model for irrigation project evaluation was developed by using internal process indicators of the rapid appraisal process. Secondly, the AHP model was applied for scoring 16 irrigation projects dealt with in FAO Water Reports 19. Then, finally, effects of the evaluation factors (e.g. managing entities, hardware, water delivery services) on irrigation project performance were analyzed by changing weights of the evaluation factors and comparing correlations between AHP model scores and crop yields. The research showed the potential and effectiveness of AHP application to irrigation project evaluation. Also, it revealed that the quality of water delivery service had a significant impact on crop production. Analysis through correlation did not imply significant relationships among water delivery services, management and hardware. However, it is inferred from the result that there would be still more room to improve the AHP model toward better evaluation of the irrigation project by adding more internal process indicators to the model