Objectives: National tuberculosis treatment guidelines suggest a regimen of 2RZE/10RE for the treatment of isoniazid resistant organisms. A retrospective clinical study of all patients treated for non-MDR-TB isoniazid-resistant organisms was undertaken.Methods: A continuous database of the patients treated between 1978–1999 inclusive was examined to determine the regimens used and the outcome of treatment for such patients.Results: Thirty-seven patients were identified. Eighteen had regimens of greater than 9 months, 19 had regimens of 9 months or less. No relapses occurred in those cases treated with a regimen of 2RZE/7RE during 12 months' minimum follow-up.Conclusions: A regimen of 2RZE/7RE may be possible for the treatment of isoniazid-resistant organisms if given either under close supervision or as a formally supervised regimen. Larger clinical studies or a controlled clinical trial are needed to confirm these initial findings.