Schistosomiasis is one of the neglected tropical diseases that pose a significant burden in developing countries, particularly in sub-Saharan Africa. Hepatosplenic schistosomiasis (HSS) is a substantial cause of morbidity and mortality. This study aimed to determine clinical patterns, outcomes and factors associated with HSS in the Harari Region of Ethiopia. An institutional-based retrospective cross-sectional study was conducted among 93 adult patients diagnosed with HSS at public hospitals in the Harari Region from December 2018 to November 2022. Data were extracted from medical records using a standardized data extraction tool. EpiData version 4.2 and SPSS version 26.0 were used for data entry and analysis. Fisher's exact test was used to identify the association between dependent and independent variables, and statistical significance was declared at p<0.05. In the current study, HSS-related mortality was recorded in 7.5% of patients. Recurrent episodes of upper gastrointestinal (GI) bleeding (p=0.04), hypotension (p=0.02), altered mental status at admission (p=0.009) and antibiotic use for the treatment of spontaneous bacterial peritonitis (p=0.04) were significant factors associated with HSS-related mortality. The study found that treatment outcomes of HSS patients were strongly associated with recurrent upper GI bleeding, hypotension, altered mental status and antibiotic use for spontaneous bacterial peritonitis treatment. The use of antibiotics for spontaneous bacterial peritonitis treatment was strongly associated with the treatment outcome of patients with HSS and was unique to our study. Adequate recording of patient data, improving chart keeping, integration of preventive and curative programs, improvement of the diagnostic tools, comprehensive treatment guidelines, early diagnosis and treatment are strongly recommended. Rigorous prospective studies that can fully reflect cause-and-effect relationships are crucial to fill fundamental evidence gaps.