Background: Since the 1990s, new insights in the physical therapy management of low back pain have been described in guidelines. Furthermore, insurance companies introduced a volume policy to control the costs for physical therapy. Objective: This study aims to establish if developments in knowledge and health policy since the 1990s have resulted in changes in the physical therapy management of patients with low back pain (LBP) in the Netherlands. Methods: Data from 3148 patients, referred because of LBP, were selected from the databases of two registration studies (1989-1992 and 2002-2003) of patients treated by physical therapists. Descriptive statistics were used to compare patient characteristics. A multi-level regression analysis was carried out to determine a change in the number of treatment sessions adjusting for patient and disease characteristics, and to control for different levels (patient and physical therapist). Results: A small decline in the number of treatment sessions was observed. In 2002, exercise therapy was the most frequently applied intervention, while massage and physical modalities were the interventions of first choice in the early 1990s. Conclusion: Our results suggest that since 1990 the management of patients with LBP by physical therapists in the Netherlands has changed. Both quality management by the profession and volume policy by government and insurance companies seem to have been instrumental in bringing about a decline in the number of treatment visits and an increase in the use of evidence-based interventions.