The present investigation was undertaken to optimize supercritical fluid extraction parameters to obtain superior quality of onion oleoresin from dried rotten onion. The effects of temperature, pressure, dynamic time and particle size were evaluated with respect to oleoresin yield, sulphur content and pyruvate content in oleoresin. Optimized condition for supercritical fluid extraction of onion oleoresin by using central composite rotatable design (CCRD) was found as 80 °C temperature, 400 bar pressure, 0.53 mm particle size and 60 min dynamic time and had yield of 1.012 % oleoresin, 31 gm sulphur content per kg of oleoresin and 10.41 µmole pyruvate per gm fresh weight of onion. Oleoresin of onion obtained by SFE and solvent extraction methods were compared and stated that SFE provided shorter extraction time, comparatively similar oleoresin yield and higher percentage of sulphur content which represents the useful sulphur containing compounds in onion. The rotten onion, can also be used to get oleoresin a very useful product, which otherwise goes as waste, without generating any revenue.