Objective To investigate the epidemiological and clinical characteristics and prognosis of visceral leishmaniasis (VL) patients in Gansu Province, so as to provide references for clinicians in the diagnosis and treatment of VL among clinician. Methods The epidemiological data, clinical manifestations, laboratory tests and prognosis of VL patients admitted to Gansu Provincial Hospital during the period between May 2011 and October 2024 were retrospectively analyzed. All statistical analyses were conducted using the software SPSS 26.0. Intergroup comparisons of categorical variables were tested for statistical significance with χ² test, while continuous variables conforming to a normal distribution were compared with independent samples t-test. Results A total of 49 VL patients were admitted to Gansu Provincial Hospital from May 2011 to October 2024, including 34 men (69.4%) and 15 female (30.6%). The patients were aged from 1 to 73 years, including 17 (34.7%) minors (age < 18 years) and 32 (65.3%) adults (age of 18 years and older). In terms of geographical locations, 49.0% (24/49) resided in Longnan City, 30.6% (15/49) in Gannan Tibetan Autonomous Prefecture, and 20.4% (10/49) in other non-endemic areas of Gansu Province. All 49 patients presented with fever and chills, predominantly demonstrating an irregular fever pattern, and splenomegaly was observed in 87.8% (43/49), hepatomegaly in 22.4% (11/49), beening in 6.1% (3/49). Comorbid complications included respiratory tract infections (44.9%, 21/49), hemophagocytic lymphohistiocytosis (HLH) (24.5%, 12/49), and abnormal liver function was noted in 14.3% (7/49). Hematological abnormalities revealed leukopenia in 81.6% (40/49), decreased hemoglobin levels in 85.7% (42/49), and thrombocytopenia in 67.3% (33/49). Among those with thrombocytopenia, 6 cases exhibited severe reduction in platelet counts (< 20 × 10⁹/L). Serum ferritin levels were quantified among 27 patients, with 96.3% (26/27) showing elevated concentrations exceeding 204 ng/L. All patients underwent biochemical tests, including aspartate aminotransferase (AST), alanine aminotransferase (ALT) and globulin measurements, and elevated AST levels were detected in 55.1% (27/49), increased ALT in 40.8% (20/49), and hyperglobulinemia in 34.7% (17/49). Among 44 patients undergoing serological testing using rK39 immunochromatographic assay, 90.9% (40/44) were tested positive, and bone marrow aspiration was performed among 43 patients, with Leishmania amastigotes identified in 83.7% (36/43) of bone marrow smears. Among these positive cases, 15 exhibited hemophagocytic syndrome. A significantly lower proportion of minor patients (6/17) experienced an interval of exceeding 30 days from disease onset to definite diagnosis as compared to adult patients (22/32, 68.7%) (χ² = 5.074, P < 0.05). Hypertriglyceridemia was observed more frequently among minors (15/17) than among adults (15/30, 50.0%) (χ² = 6.871, P < 0.05), and hemophagocysis in bone marrow was less common among minor patients (3/17) compared to adults (14/30, 46.7%) (χ² = 3.958, P < 0.05). Among the 49 patients, 37 were diagnosed with uncomplicated VL, while 12 presented with HLH-associated VL. The mean platelet count was (46.83 ± 25.54) × 10⁹/L among HLH-associated VL patients, which was significantly lower than among uncomplicated VL patients [(103.14 ± 65.61) × 10⁹/L] (t = 4.309, P < 0.05). Conversely, the mean serum ferritin level was significantly higher among HLH-associated VL cases [(4 440.18 ± 1 140.88) ng/ml] than among uncomplicated VL cases [(1 483.35 ± 1 551.36) ng/ml] (t = -5.509, P < 0.05). Among 46 patients who received treatment at Gansu Provincial Hospital, 29 were treatment naive and 17 had received prior therapies, and all these patients were administered intravenously with sodium stibogluconate (SSG), including one death after 14 days post-treatment due to hemophagocytic syndrome and respiratory failure. Two patients required alternative therapeutic regimens: one was switched to amphotericin B cholesteryl sulfate complex due to adverse effects (nausea, vomiting, abdominal pain and diarrhea) during intravenous infusion of SSG, and another was switched to the same alternative regimen due to persistent detection of Leishmania amastigotes in bone marrow smears after four treatment cycles. All surviving patients showed clinical improvements compared to admission status. Conclusions For patients from VL-endemic areas presenting with fever, hepatosplenomegaly, and bicytopenia or pancytopenia on routine blood tests, prompt serological testing (rK39 immunochromatographic assay) or bone marrow aspiration should be performed. Upon diagnosis as VL, standardized treatment with antileishmanial agents and anti-inflammatory medications should be initiated in a timely manner to improve patients’ prognosis.