Background: Primary Care Triage is a patient sorting system used in some primary health care clinics (PHCCs) in Sweden where patients with musculoskeletal disorders (MSD) are triaged directly to physiotherapists. The purpose of this study was to investigate whether sorting/triaging patients seeking a PHCC for MSD directly to physiotherapists affects their utilization of medical services at the clinic for the MSD and to determine whether the effects of the triaging system vary for different sub-groups of patients., Methods: A retrospective case-control study design was used at two PHCCs. At the intervention clinic, 656 patients with MSD were initially triaged to physiotherapists. At the control clinic, 1673 patients were initially assessed by general practitioners (GPs). The main outcome measures were the number of patients continuing to visit GPs after the initial assessment, the number of patients receiving referrals to specialists/external examinations, doctors' notes for sick-leave or prescriptions for analgesics during one year, all for the original MSD., Results: Significantly fewer patients triaged to physiotherapists required multiple GP visits for the MSD or received MSD-related referrals to specialists/external examinations, sick-leave recommendations or prescriptions during the following year compared to the GP-assessed group. This applies to all sub-groups except for the group with lower extremity disorders, which did not reach significance for either multiple GP visits or sick-leave recommendations., Conclusions: The reduced utilization of medical services by patients with MSD who were triaged to physiotherapists at a PHCC is likely due to altered management of MSD with initial assessment by physiotherapists.