The Roundtable on Sustainable Palm Oil (RSPO) was founded in 2004 to promote the expansion and use of sustainable oil palm products through credible global standards and multistakeholder governance. Though RSPO was widely accepted as a reliable standard, it still lacks into certain extent quantification element to enable proper and smoother standardized measurement. To eliminate this problem, a new indexing method called Environmental Sustainability Index (ESI) was designed and proposed. The paper presents a case study to demonstrate the real-life application of the ESI-RSPO Integrated Environmental Sustainability Index Framework. The framework designed by the fusion of the key features of the ESI of measuring the overall progress towards environmental sustainability and RSPO of encouraging the growth and use of sustainable oil palm products, exhibits an organized, procedural and scientific pathway of measuring the environmental performance of palm oil manufacturing entities. Quantitative approach from ESI coupled with qualitative valuation from RSPO brings about tremendous advantages in the environmental sustainability context in particular by clearly showing where an entity is positioned in relation to the desired target. The results of this case study clearly pinpoint the environmental parameter outlier and prove that integration of ESI and RSPO will not only promote objectivity but also consistency of results across different production units. Both qualitative and quantitative measurement, operating in conjunction, is very much needed in a system as critical and dynamic with complex inter-relationship and linkages between various subsystems such as environmental sustainability.