Mastitis is major health issue compromising the welfare of dairy cows. Individual behaviour of dairy cows few days before mastitis is a potential tool for higher detection accuracy. However, little is known about the existence of behavioural patterns usually expressed by cows in healthy conditions that are associated with the subsequent onset of mastitis. This study aimed to determine whether cows that will subsequently be affected by mastitis express distinctive behavioural patterns compared to the ones that stay healthy throughout lactation. Daily hours spent standing, lying down, walking, ruminating and eating were recorded from calving to 15 d prior mastitis using accelerometer collars in two commercial farms in Italy. The mastitis group (n=16) was constituted with the cows suffering from one mastitis during lactation. A control group of healthy cows (n=16) balanced for parity and lactation stage has been constituted afterwards. The group effect (mastitis vs no mastitis) on the intercept and the slope of the regression curve of each individual cows for all behaviours was analysed using ANOVA. Cows from the mastitis group spent less time lying (9.25 vs 9.66 h/d) and more time walking (2.69 vs 2.40 h/d) and ruminating (8.56 vs 8.14 h/d) than control cows 100 days before the onset of mastitis (P<0.001). Behavioural changes over time before mastitis also differed as shown by the lower slope coefficient for lying, walking and ruminating in mastitis than in control cows (P<0.001). This study may suggest that cows suffering from mastitis exhibited different lying, walking and ruminating durations, months before the onset of the disease. Further investigations are needed to confirm if differences in behavioural patterns can be considered as promoters of disease.