Objective To evaluate the feasibility of pulse transit time (PTT) arousals as an index of sleep fragmentation in patients with obstructive sleep apnea hypopnea syndrome (OSAHS). Methods Individuals referred for evaluation of possible OSAHS underwent overnight polysomnography (PSG). Three conventional indices of sleep fragmentation [electroencephalography (EEG) arousals, apnea/hypopnea index (AHI), oxygen desaturation index (ODI)], PTT arousals, and Epworth sleepiness scale (ESS) were compared. Results PTT arousals were positively correlated with EEG arousals (r= 0.746, P<0.001), AHI (r= 0.786, P<0.001), and ODI (r= 0.665, P<0.001), respectively. But, both PTT arousals and EEG arousals had no correlation with ESS (r= 0.432, P=0.201; r= 0.196, P=0.591, respectively). Conclusion PTT arousals are correlated well with other standard measures estimating severity of OSAHS and potentially a non-invasive marker with which to measure the sleep fragmentation in patients with OSAHS. Objective To evaluate the feasibility of pulse transit time (PTT) arousals as an index of sleep fragmentation in patients with obstructive sleep apnea hypopnea syndrome (OSAHS). Methods Individuals referred for evaluation of possible OSAHS underwent overnight polysomnography (PSG). Three conventional indices of Results of PTT arousals, and Epworth sleepiness scale (ESS) were compared. Results PTT arousals were positively correlated with EEG arousals (r = 0.72, P <0.001), AHI (r = 0.786, P <0.001), and ODI (r = 0.665, P = 0.201; r = 0.196, P = 0.591, respectively). Conclusion PTT arousals are correlated well with the standard measure of severity of OSAHS and potentially a non-invasive marker with to measure the sleep fragmentation in patients with OSAHS.