It has been suggested that ICU follow-up clinics can offer support for ICU survivors and their relatives. However, implementation of such clinics can be challenging. We explored the barriers to implementation of an ICU follow-up program from the healthcare providers' perspective. This was a mixed methods study with a triangulation design conducted over the 7-month pilot period of an ICU follow-up program. The quantitative analysis showed that two main tasks within the program took the most time to be completed: training and tracking. Training new healthcare professionals to acquire the necessary competences for the follow-up clinic was the most time-consuming task [30 min (IQR 13-56)]. Tracking patients, which consists of keeping records of a patient during the hospital stay and when discharged, was the second most time-consuming task [15 min (IQR 10-20)]. We recorded 291 items of qualitative data from the 12 team members who participated. The qualitative analysis identified three domains that were crucial barriers for program implementation: Luhr et al. (2019) [1] organization (37.1%), Máca et al. (2017) [2] engagement (38.5%), and (Gayat et al., 2018 [3]) resources (24%). In agreement with the quantitative data, training and tracking were perceived by participants as laborious tasks and key barriers to implementation of the ICU follow-up program. Despite the expectation that resources would be the most important barrier, they were not considered as such by our participants being only mentioned in 13.4% of our qualitative reports; when mentioned, this barrier was related mostly to insufficient numbers of staff members. Awareness of those barriers can help healthcare providers and ICU managers in developing strategies adapted to overcome constraints, thus facilitating the implementation process.