Multidrug-resistant bacteria (MDRB) carriage may impact the outcomes of intensive care unit (ICU) patients. In this study, we aimed to assess the effect of MDRB-related infection and colonization on the day60 mortality rate. We conducted a retrospective, observational study in a single university hospital ICU. From January 2017 to December 2018, we screened all patients admitted to the ICU for at least 48h for MDRB carriage. The primary outcome was the mortality rate on day60 after MDRB-related infection. The secondary outcome was the mortality rate on day60 of non-infected but colonized patients with MDRB. We considered the effect of potential confounders, such as the occurrence of septic shock, inadequate antibiotic therapy, Charlson score, and life-sustaining limitation order. We included 719 patients during the aforementioned period; of this number, 281 (39%) had a microbiologically documented infection. MDRB was found in 40 (14%) patients. The crude mortality rate in the MDRB-related infection group was 35% vs. 32% in the non-MDRB-related infection group (p = 0.1). Logistic regression showed that MDRB-related infection was not associated with excess mortality, with an odds ratio of 0.52 and a 95% confidence interval from 0.17 to 1.39 (p = 0.2). Charlson score, septic shock, and life-sustaining limitation order were significantly associated with an increased mortality rate on day60. No effect of MDRB colonization on mortality rate on day60 was highlighted. MDRB-related infection or colonization was not associated with an increased mortality rate on day60. Other confounders, such as comorbidities, may account for a higher mortality rate.