It was the aim of this study to investigate resting and sleep in sows with regard to behaviour and cardiac activity. First, in total 32 sows in four different farrowing systems (two farrowing pens, two farrowing crates) were directly observed on two consecutive days during both late pregnancy and in early lactation. Behavioural parameters such as lying position and twitches of legs, eyes, trunk and body were used to determine the sleep phases. In the second part of the study, cardiac activity was assessed on two consecutive days in 11 early lactating sows, which were kept in a farrowing pen and a farrowing crate, respectively. Sows in farrowing pens showed less sleep phases; pregnant sows had higher proportions of NREM sleep. There were no differences between housing systems with regard to heart rate and heart rate variability. Heart rate during NREM and REM was lower than during being awake. RMSSD and SD1 were lower during waking than during drowsing. HF n.u./LF n.u. during waking were lower/higher than during NREM and REM. The LF/HF ratio was higher during waking than during REM. A statement concerning the well-being of the sows could not be made at present. That would require more, particularly long-term investigations.