Dropout from a rehabilitation programme often occurs in patients with chronic nonspecific low back pain of non-native origin. However, the exact dropout rate is not known. The objective of this study was to determine the difference in dropout rate between native and non-native patients with chronic nonspecific low back pain participating in a rehabilitation programme in The Netherlands. A retrospective study (n = 529) of patient files was performed in two rehabilitation centres and two rehabilitation departments of general hospitals in The Netherlands. Patient files were checked for diagnosis, status of origin, sex, age and outcome, that is, reason for finishing treatment. The difference in dropout rate between patients of Dutch and non-Dutch origin was tested by [chi][superscript 2] tests and logistic regression-analysis, controlling for age, sex, type of rehabilitation institute and phase of the rehabilitation programme. Dropout occurred among one fifth (18.7%) of the total patient population. Dropout among patients of non-Dutch origin was twice as high as among native Dutch patients (P less than 0.001). In regression analyses dropout was related to status of non-Dutch origin, treatment in a rehabilitation centre and the diagnostic phase of a rehabilitation programme. In conclusion, patients of non-Dutch origin drop out considerably more frequently than native Dutch patients. Dropout is higher in the diagnostic phase than in the treatment phase and in rehabilitation centres than in hospitals. Future research should clarify the reasons for the high dropout rate in patients of non-native origin.