<p>The growing global demand for cleaner and renewable energy sources has intensified interest in bioethanol production from agro-industrial byproducts such as molasses. This study presents a comprehensive life cycle assessment of bioethanol production from sugarcane molasses to evaluate its environmental sustainability, energy efficiency, and associated uncertainties. The analysis employs the ReCiPe 2016 and cumulative energy demand methods to quantify midpoint and endpoint environmental impacts along with total energy use across the production chain. A gate-to-gate system boundary was adopted, encompassing molasses preparation, fermentation, distillation, and dehydration processes. Results indicate that electricity and steam generation are the dominant contributors to environmental burdens, particularly influencing global warming, fine particulate matter formation, and human toxicity categories. The total energy requirement was found to be 26.98&#xa0;MJ per kg of ethanol produced, with fossil energy accounting for 93% of this demand. Despite this, the process demonstrated a slightly positive energy balance, reflected by a net energy ratio of 1.04, confirming marginally favorable energy performance. Uncertainty analysis using Monte Carlo simulation revealed stable results with low variability, indicating model robustness. Human non-carcinogenic toxicity and global warming potential were identified as the impact categories contributing most significantly to the overall uncertainty in the results. Overall, the findings suggest that molasses-based bioethanol is a viable renewable fuel option with potential to reduce fossil energy dependence, provided that efficiency improvements in electricity and steam usage are implemented. The study underscores the importance of integrating energy and uncertainty analyses for more reliable environmental sustainability assessments of biofuel systems.</p>