Irrigation tanks formed the lifeline of village economy. The Government of Karnataka amended its Irrigation Act in 1965 and Participatory Irrigation Management (PIM) was brought under the domain of Cooperative Act and Water Users Cooperatives were formed to managed and operate the tanks. The present study was undertaken to assess the transaction cost in irrigation tank management in central dry zone of Karnataka. Two tanks Bukkarayanakere (farmers managed) and Ayyanakere (Minor Irrigation Department managed) were considered for the study. The results revealed that, total transaction cost incurred was high in Minor Irrigation Department managed tank or defunct water users association (` 1,06,085 per year) than farmers managed tank or active water users association (` 61,480 per year). This is because of free riding problem that prevailed in the Minor Irrigation Department managed tank command. Educating the farmers regarding the benefits of collective action is necessary to reduce the transaction cost.