BACKGROUND: Gaucher disease (GD) is an autosomal recessive disorder characterized by excessive accumulation of glucosylceramide in multiple organs. This study was performed to determine the detection rate of GD in a selected patient population with unexplained splenomegaly in Korea. METHODS: This was a multicenter, observational study conducted at 18 sites in Korea between December 2016 and February 2020. Adult patients with unexplained splenomegaly were enrolled and tested for beta-glucosidase enzyme activity on dried blood spots (DBS) and in peripheral blood leukocytes. Mutation analysis was performed if the test was positive or indeterminate for the enzyme assay. The primary endpoint was the percentage of patients with GD in patients with unexplained splenomegaly. RESULTS: A total of 352 patients were enrolled in this study (male patients, 199; mean age, 48.42 yr). Amongst them, 14.77% of patients had concomitant hepatomegaly. The most common sign related to GD was splenomegaly (100%), followed by thrombocytopenia (44.32%) and, anemia (40.91%). The beta-glucosidase activity assay on DBS and peripheral leukocytes showed abnormal results in sixteen and six patients, respectively. Eight patients were tested for the mutation, seven of whom were negative and one patient showed a positive mutation analysis result. One female patient who presented with splenomegaly and thrombocytopenia was diagnosed with type 1 GD. The detection rate of GD was 0.2841% (exact 95% CI, 0.0072‒1.5726). CONCLUSION: The detection rate of GD in probable high-risk patients in Korea was lower than expected. However, the role of hemato-oncologists is still important in the diagnosis of GD.