A field experiment was conducted at the Main Agricultural Research Station, Agriculture College, Dharwad, during 2002-03 to study the effect of different level of NPK on quality of sweet corn grown on Vertisols of zone-8 of Karnataka. Application of P and K at recommended levels of grain maize i.e., 75 kg P per ha and 37.5 kg K per ha along with 75% of recommended level of N of grain maize i.e., 112.5 kg N per ha was found to be necessary to increase the quality parameters viz., non-reducing sugar, total sugar and protein content. Reduction of N below 75% and P and K below 100% of recommended dose of grain maize not only accounted for reduction in total sugar and protein content but also in sweetness of grains.