Respiratory drive is tightly controlled by the carbon dioxide levels. We tested the hypothesis that sequences of sleep apnoea (obstructive, central or mixed), hypopnoea and flow limitation are characterized by different levels of transcutaneous CO₂ (PtcCO₂). Polygraphic recordings (n = 555) from patients with suspected sleep-disordered breathing (SDB) were retrospectively screened to find sequences (5 min or 10 events) of both SDB and steady breathing. Eighty-eight SDB sequences from 44 patients were included and PtcCO₂ and SpO₂ values were collected. PtcCO₂ values during sequences were normalized by setting wakefulness level as 100%. In terms of PtcCO₂, apnoea sequences with central component (central (n = 7) and mixed (n = 3) apnoea) did not differ from wakefulness (102.0% vs 100%, p = 0.122) whereas obstructive apnoea (105.8%, p < 0.001) and hypopnoea did (105.4%, p < 0.001). PtcCO₂ during flow limitation was higher than that during any other sequence, including steady breathing (112.2% vs 108.4%, p = 0.022). Continuous PtcCO₂ monitoring during sleep adds to the understanding of different SDB phenotypes.