Aim. To: (a) describe how telephone nurses define a frequent caller; and (b) describe their experiences with calls from frequent callers to primary healthcare centres. Background. Telephone nursing has been noted to be a cost-effective method to enhance access to and use of health care. Some patients use these services extensively and are called 'frequent callers'. Little is known about this group of callers, the reasons behind these calls and telephone nurses' experiences and strategies to manage the calls. Design. Descriptive design with a qualitative inductive approach. Methods. Interviews were conducted with ten telephone nurses in Sweden in 2015. Qualitative content analysis was conducted. Results. A main theme was established, called 'Balancing between the experienced and assessed needs', which described the telephone nurses' experiences with calls made by frequent callers to primary healthcare centres and was further described in five categories with 15 subcategories. The categories described telephone nurses' definitions of frequent callers, telephone nurses' views of the underlying reasons for the calls, challenges related to frequent callers, experiences with an increased work load and strategies used to manage and help frequent callers. Conclusion. Frequent callers were commonly encountered by telephone nurses' in this study. Their calls were experienced as complex and demanding to manage. The findings point to needs for guidelines and routines to improve the care of frequent callers. In addition, support and training in communication skills to encounter this group of callers in an optimal and safe way may be required.