A study was carried out on nine ewes suckling single (five) or twin (four) lambs, born in July, to observe the changes in daily distribution of suckling behaviour during lactation, and to determine whether suckling intensity influenced the time taken for Texel ewes to return to estrus. Nine other ewes, which had lambed in March and from which lambs were removed at the beginning of July, served as controls for the occurrence of estrus. Recording suckling behaviour during a 24-h period weekly, from the first to the ninth week, allowed us to conclude that: (1) sucklings were more frequent during the day than during the night ( P<0.01) with a trend to increase in the morning; (2) the frequency and the duration of suckling decreased with age of the lambs; (3) the frequency of suckling did not differ among single and twin lambs, but the mean and total duration of suckling were higher within twin lambs; (4) suckling delayed the return to estrus for 14 days ( P<0.01), but no difference was observed between dams suckling singles and twins. The suckling intensity and the duration of post-partum anestrus were not linked. The inhibitory effect of suckling on the resumption of estrus is thus not related to the intensity of the stimuli.