This study investigated patients’ experiences of loneliness in professional caring relationships and their associations with perceived recovery, health, psychological distress, and general loneliness in life. The sample consisted of 406 patients who had undergone breast cancer or heart surgery 6 months earlier. The data were collected in May 2014-March 2015 using a postal survey including the Caring Loneliness Scale (CARLOS), questions concerning perceived health and recovery, 12-item General Health Questionnaire (GHQ-12), and a question concerning perceived general loneliness in life. Data analysis was done using Mann–Whitney U test and Kruskal–Wallis test. The variables showing a statistically significant association with professional caring loneliness were perceived health, recovery, psychological distress, and general loneliness in life. It is necessary for health care professionals to identify the phenomenon of this dimension of loneliness because it is bound to affect patients’ experiences. Further studies with different patient groups are required.