Background : Healthcare-associated infections (HAIs) are with high rates of mortality and an additional cost, in onco-hematology patients. Aim  : The study aims to assess the prevalence trends of HAIs in the onco-hematology ward of the Tunisian National Bone Marrow Transplant Center (NBMTC), and to determine the principal associated risk factors. Methods: Six repeated point prevalence surveys were conducted, from May 2018 to March 2019, using a two months interval. All patients hospitalized in the day of the survey were included. Risk factors of HAIs were expressed as odds ratios (ORs) with 95% confidence intervals (CIs). They were assessed using a logistic regression model. Results: Nineteen patients out of a total of 74 patients have been diagnosed with 19 HAIs, representing a prevalence of 25.7%. No significant downward or upward trend of prevalence was revealed over time (p=0.3). The most common HAI was respiratory tract infection (57.9%) with a prevalence of 14.9%. Multiple logistic regression analysis revealed that HAI was significantly associated with neutropenia (Adjusted OR: 14; 95% CI: 1.5-127; p=0.01) and duration of central venous catheter (Adjusted OR: 1.1; 95% CI: 1-1.2; p=0.005). Conclusion: High prevalence of HAIs in our center with a high rate of mortality, requiring identifying potential problems in infection control practices.