Background/Aims: The gastric extranodal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue (gastric MALT lymphoma) are mostly related to Helicobacter pylori infections. However, chromosomal aberration involving translocation t(11;18) is also frequently reported in these patients. Methods: The study was a retrospective review and analysis of electronic medical records to assess the factors which affect complete remission (CR) in patients with gastric MALT lymphoma. Based on the medical records, subjects with gastric MALT lymphoma were enrolled consecutively from January 2004 to December 2021. Results: Among the 77 subjects who were found with gastric MALT lymphoma in the database, 65 cases with complete records were analyzed. Of these, 66.2% (43/65) were H. pylori positive. Genetic analyses for t(11:18) were done on 41 subjects. The t(11:18) chromosomal translocation with MALT1:BIRC3 fusion was found in 31.7% (13/41) of the subjects. With H. pylori eradication therapy, 75% (21/28) of the subjects without t(11:18) achieved CR. However, only 23.1% (3/13) subjects with t(11:18) could achieve CR (p-value=0.009). In the H. pylori-positive group, 85.7% (18/21) subjects without t(11:18) achieved CR with eradication therapy, but 71.4% (5/7) subjects with t(11:18) failed to achieve CR (p-value=0.004). In the H. pylori-negative group, 42.3% (3/7) of the subjects without t(11:18) achieved CR with eradication therapy. However, 83.3% (5/6) of H. pylori-negative subjects with t(11:18) failed to achieve CR with eradication therapy and needed additional radiotherapy (p-value=0.396). Conclusions H. pylori negativity and the presence of t(11:18) were both risk factors for failure to achieve CR with H. pylori eradication therapy as the first line of treatment.