Background Eliminating hepatitis C virus (HCV) infections is a goal set by the World Health Organization. This has become possible with the introduction of highly effective and safe direct-acting antivirals (DAA) but limitations remain due to undiagnosed HCV infections and loss of patients from the cascade of care at various stages, including those lost to follow-up (LTFU) before the assessment of the effectiveness of the therapy. The aim of our study was to determine the extent of this loss and to establish the characteristics of patients experiencing it. Methods Patients with chronic HCV infection from the Polish retrospective multicenter EpiTer-2 database who were treated with DAA therapies between 2015 and 2023 were included in the study. Results In the study population of 18,968 patients, 106 had died by the end of the 12-week post-treatment follow-up period, and 509 patients did not report for evaluation of therapy effectiveness while alive and were considered LTFU. Among patient