Reusing wastewater for agricultural irrigation offers a solution to alleviate strain on freshwater resources. The cassava starch industry’s wastewater has been repurposed for irrigating renewable energy crops like Napier grass. However, research on how this practice affects soil organic matter and compaction remains limited. This study aimed to investigate the long-term effects of cassava wastewater reuse for Napier grass cultivation on these soil properties. Soil samples were collected at depths of 0-15, 15-30, and 30-50 cm from areas using cassava wastewater for Napier grass irrigation for over 10 years, compared to areas without wastewater use. Results showed significantly higher soil organic matter and lower soil compaction in areas using cassava wastewater. The highest organic matter content was found in areas influenced by cassava wastewater without Napier grass cultivation, followed by areas using a siphon system with Napier grass, pump system with Napier grass, and lastly, areas unaffected by either cassava wastewater or Napier grass. Conversely, the lowest soil compaction was observed in areas using a siphon system with Napier grass, followed by areas influenced by cassava wastewater without Napier grass, pump system with Napier grass, and finally, areas unaffected by either cassava wastewater or Napier grass. This study concludes that reusing cassava wastewater for Napier grass cultivation can enhance soil organic matter content and reduce soil compaction, contributing to improved soil health and sustainable agricultural practices.