Nitrogenous fertilizers are the most important contributing factor for the improvement of crop yields, since last one and half decade. Though farmers are advised by the extension workers to use recommended dose of nitrogenous fertilizers, it is not adopted because of the physical outcome of fertilizer application. The excessive use of nitrogenous fertilizers has resulted in higher plant protection chemicals and has further resulted in increase in pest incidence, but also high cost structure in the production process. In order to examine different dimensions of economic aspects of selected inputs, a study was carried out in Tungabhadra project (TBP) area of Karnataka during the year 2010-11 for which multistage random sampling design was employed for a sample size of 90 farmers. The study revealed that the extent of application of insecticides increased from 5413ml/g a.i/ha to 7338ml/g a.i/ha, fungicides application from 805 ml/g a.i/ha to 1283ml/g a.i/ha and weedicides from 4853ml/g a.i/ha to 7625 ml/g a.i/ha from nitrogen level 1 (upto 50% RD of nitrogen) to nitrogen level 3(>100% RD of nitrogen), respectively. Thus, the total cost incurred towards plant protection chemicals ranged from ` 15886/ha to ` 24442/ ha from nitrogen level 1 to 3, respectively in paddy cultivation. Thus, emphasis must be given for adoption of Integrated Pest Management (IPM) and Integrated Nutrient Management (INM), which needs promotion through different extension strategies to minimize the losses.