To study retinal nerve fiber layer (RNFL) thickness in patients with retinitis pigmentosa (RP).Cross-sectional observational study.One hundred and thirty-seven eyes of 137 patients with RP were examined. The effect of age, gender, laterality, inheritance trait, spherical equivalent refractive error, visual acuity, and the extent of visual field defect on RNFL thickness measured with optical coherence tomography were analyzed by a multiple linear regression model.The average RNFL thickness was 104.1+/-21.7 microm. The multiple R(2) for the model was 0.349. Among the variables studied, ageing and being male were significant risk factors for thinner RNFL thickness. RNFL thickness was not correlated with inheritance trait, laterality, refractive error, visual acuity, or the extent of visual field defect.RNFL thickness in RP patients was not correlated with visual function but ageing as in the normal subjects. Currently proposed therapies, including photoreceptor rescue/transplantation and visual prosthesis, are based on the premise that the inner retinal structures are relatively retained despite the profound loss of photoreceptors. The present result supports this notion.