Sulcospira testudinaria, a freshwater gastropod prevalent in Indonesian aquatic environments, serves as a bioindicator for assessing water quality. This study examined the hemocyte profile of S. testudinaria to evaluate water quality in Ranu Grati, Pasuruan Regency, East Java. Water samples were obtained from four study stations with three replications biweekly from August to October 2024. Essential water quality metrics, such as temperature, pH, Dissolved Oxygen (DO), Biological Oxygen Demand (BOD), Total Suspended Solids (TSS), Total Dissolved Solids (TDS), and ammonia, were assessed. The analysis of hemocytes included the assessment of Total Hemocyte Count (THC) and Differential Hemocyte Count (DHC) to investigate physiological responses to environmental variables. The results indicated discrepancies in water quality, with Stations 3 and 4 exhibiting heightened amounts of TSS, BOD, and ammonia, signifying pollution. The circumstances markedly influenced the hemocyte profile, resulting in elevated THC and modified ratios of granulocytes, hyalinocytes, and semi-granulocytes. Canonical Correspondence Analysis (CCA) demonstrated significant connections between suboptimal water quality measures and stress responses in S. testudinaria. The results underscore the efficacy of S. testudinaria as a bioindicator, offering essential insights for the sustainable management of freshwater ecosystems.