Background Sleep-disordered breathing (SDB) is common in patients with severe chronic respiratory failure, but there are no data describing the prevalence of SDB among patients listed for lung transplantation or the effect of transplantation on SDB. We sought to determine the prevalence and impact of SDB before and after lung transplantation. Methods We performed polysomnography (PSG) on 117 of 183 (64%) consecutive patients (64 males, 53 females) listed for lung transplantation between 1998 and 2001. SDB was defined as respiratory disturbance index (RDI) ≥10 or an awake oxygen saturation >90% and ≥10% of total sleep time (TST) with oxygen saturation (SaO2) ≤90%. Room-air PSG was repeated post-transplant in 25 subjects. Results Eighty of 117 patients had PSG on room air, 30 of 117 on oxygen and 7 of 117 on non-invasive ventilation. Thirty two of 80 patients (40%) with room-air PSG had SDB: 18 of 32 (56%) had ≥10% of TST with SaO2 ≤90% and RDI <10, and 14 of 32 (44%) had RDI ≥10. Eight of 32 had both ≥10% of TST with SaO2 ≤90% and RDI ≥10. Nine of 30 (30%) patients on oxygen and 1 of 7 on NIV had SDB. Post-transplant, SDB resolved in 6 of 11 patients with the condition, but 4 of 14 without previous SDB developed new SDB. SDB (treated or not) did not influence whether patients survived to transplant ( p = 0.8), nor did a diagnosis of SBD prior to transplant influence post-transplant survival ( p = 0.7). Conclusions SDB is common before lung transplantation. Lung transplantation improves oxygenation, but new-onset SDB may occur after the procedure.