BACKGROUND: To better manage patient demand, some general practices have implemented a 'telephone first' approach in which all patients seeking a face-to-face appointment first have to speak to a GP on the telephone. Previous studies have suggested that there is considerable scope for this new approach, but there remain significant concerns. AIM: To understand the views of GPs and practice staff of the telephone first approach, and to identify enablers and barriers to successful adoption of the approach. DESIGN AND SETTING: A qualitative study of the telephone first approach in 12 general practices that have adopted it, and two general practices that have tried the approach but reverted to their previous system. METHOD: A total of 53 qualitative interviews with GPs and practice staff were conducted. Transcriptions of the interviews were systematically analysed. RESULTS: Staff in the majority of practices reported that the approach was an improvement on their previous system, but all practices experienced challenges; for example, where practices did not have the capacity to meet the increase in demand for telephone consultations. Staff were also aware that the new system suited some patients better than others. Adoption of the telephone first approach could be very stressful, with a negative impact on morale, especially reported in interviews with the two practices that had tried but stopped the approach. Interviewees identified enablers and barriers to the successful adoption of a telephone first approach in primary care. Enablers to successful adoption were: understanding demand, practice staff as pivotal, making modifications to the approach, and educating patients. CONCLUSION: Practices considering adopting or clinical commissioning groups considering funding a telephone first approach should consider carefully a practice's capacity and capability before launching.