The WHO established that medication errors are the most common and preventable errors and represent an expenditure of 42 billion U.S. dollars annually. The risk of medication errors increases in transitions between levels of care, mainly from hospital care to primary healthcare after hospital discharge. In this context, communication is a key element in the safety of the medication reconciliation process. The aim of this paper was to describe the barriers to, and facilitators of, effective communication during the medication reconciliation process at hospital discharge in people over 65 years of age, from the perspective of primary healthcare professionals. A qualitative descriptive study was designed, and in-depth interviews were conducted with 21 individuals, of whom 13 were nurses and 8 were physicians. This study was carried out with healthcare professionals belonging to primary healthcare centres in Huelva (Spain). Following content analysis of the discourses we identified 19 categories, grouped into three areas: interlevel communication, communication between primary healthcare professionals, and communication between healthcare professionals and patients/caregivers. The barriers found mainly relate to the adequacy and use of technological tools, time available, workload and the level of collaboration of patients/caregivers. Facilitating elements for communication in medication reconciliation included technologies, such as computerized medical history, protocolization of clinical sessions, the presence of case management nurse and interdisciplinary teamwork.