The aim of this study was to investigate the daily rhythms of total locomotor activity (TLA) in mares during the prepartum and postpartum periods and the existence of these rhythms at the time of birth in neonatal foals. For this purpose, TLA was recorded in 9 mares starting from the third day preceding the date of foaling until 3 days after foaling. The TLA was recorded in the newborn foals starting from 2 to 6 hours after birth until the third day of life. Animals were housed in individual straw-bedded boxes (4.0 × 3.5 m) under natural photoperiod and ambient temperature. Animals were fed twice a day (7 am; 5 pm) and were allowed to go to the paddock during the day (from 10 am to 4 pm). Mares showed a diurnal activity, and the total amount of daily activity statistically changed during the 6 days of monitoring. Activity was statistically higher in the prepartum period than in the postpartum period. In foals, a statistical increase of the total amount of daily activity was observed in the 3 days of monitoring, but no differences were observed in the amount of activity recorded during the photophase and the scotophase. Both in mares and foals, rhythmicity was observed on the second and second days postpartum, and the acrophase of rhythm did not change during the monitored period. The mean level and amplitude of rhythm were higher in foals than in mares. In mares, the amplitude was lower during day 3 postpartum compared to days 1 and 2 prepartum. Robustness of rhythm in mares was lower in day 3 postpartum compared to days 1 and 3 prepartum. In conclusion, although TLA significantly changed from the 3 days prepartum to the 3 days postpartum, the acrophase of rhythm was the same in all experimental conditions and was opposite to that observed in foals.