The co-digestion of Chromolaena odorata with poultry manure was evaluated in this study. Two samples of the weed: (A: which was pre-treated with mechanical, chemical and thermal methods) and (B: which was pretreated using mechanical and chemical methods only) were separately digested with poultry manure. Biogas generation started from the 2nd to 4th and 4th to 7th day for samples 'A' and 'B' respectively. The most desired actual biogas yield from samples 'A' and 'B' were 3884.20 and 2544.70 (10(4) m(3)/kg VS) respectively and the gas composition was 68 +/- 2% Methane and 20 +/- 2% Carbon dioxide for sample A while it was 62 +/- 3% Methane and 22 +/- 2% Carbon dioxide for sample B. In all, there was a 38.06% increase in gas generation in 'A' over 'B'. The coefficient of determination (R-2) for the Response Surface Methodology (RSM) model (0.9009) was high suggesting high accuracy in the modeling and prediction. The worldwide usage of C. odorata is encouraged. (C) 2016 Elsevier Ltd. All rights reserved.