A study was conducted to evaluate various unconventional feed ingredients by in vitro gas production technique (IVGPT). Six crossbred cattle of age 9-12 months were randomly selected from University Livestock Farm, Mannuthy. All the animals were maintained on total mixed ration (TMR) containing concentrate mixture Type II prepared using conventional feed ingredients and Hybrid Napier grass in 50:50. These animals were used as rumen liquor donors for conducting IVGPT. Thirty locally available unconventional feeds were collected from Thrissur, Kerala and their proximate analysis was done. Thirty iso-caloric and iso-nitrogenous total mixed rations containing 13- 14 per cent crude protein and 65-70 per cent total digestible nutrients were prepared with these unconventional feed ingredients replacing conventional ingredients on nutrient basis. These thirty TMR’s were then subjected to IVGPT to estimate various fermentation parameters. The cluster analysis of the results revealed that among the unconventional feeds dhanwantharam thailam residues and rape seed cake can be utilized as ruminant livestock feed ingredients.