In the present study, the influence of process parameters and pretreatment on biogas production, volatile solid degradation and COD degradation during anaerobic digestion of food waste were experimentally investigated. Using Taguchi based Grey relational analysis, the optimum condition for anaerobic digestion was found. Taguchi technique was coupled with grey relational analysis to obtain a grey relational grade for evaluating multiple outputs. A L-16 orthogonal array was selected and designed for five parameters varied through four levels by applying Taguchi's design of experiments. The optimum level values of parameters obtained for anaerobic digestion of food waste is solid concentration of 7.5% TS, pH of 7, temperature of 50 degrees C, C/N ratio of 20.19 and ultrasonication pretreatment. Percentage contribution of input parameters on output was determined using ANOVA. The results showed that pretreatment is the prominent parameter that contributes towards output responses followed by pH, solid concentration, temperature and C/N ratio. (C) 2016 Elsevier Ltd. All rights reserved.