To account the total greenhouse gas (GHG) emissions of commodities by life cycle analysis (LCA) is valuable among the global mitigation actions. Although LCA is widely applied in many countries, data of one country could not be applied to another due to country specific. LCA study is limited in Thailand, since most required data are not available and boundary assumptions are different and limited. Conventional LCA is performed by inventory approach, which is laborious, time consuming and depending on individual boundary assumptions. This article uses the input-output analysis to evaluate all embedded emissions by extending the boundary of upstream production to infinite subprocess chains. All possible sources of GHG emissions in any process chains are evaluated by following the revised 1996 IPCC guidelines. Results present total emission factors of Thai commodities and delineate the significance of higher order subprocess accounting what is usually truncated in inventory analysis.