Some breeding ecology features of a small colour‐ringed Cetti's warbler population was studied for four years in the countryside near Vicenza (northeastern Italy). Dry brambles (54.9%) proved to be by far the most preferred site for nest building. The commonest clutch size was of four eggs, and 94.1% of completed clutches were of three or four eggs. Clutch size decreased throughout the breeding season. About half of the yearly female population was actually double‐brooded. This percentage seemed influenced mainly by the result of the first clutch, Cetti's warbler generally laying only repeat clutches after an unsuccessful first one. One‐year‐old Females had a smaller first clutch size, nestling weight, and number of fledglings than older females. Hatching success was higher in repeat (87.7%) than in first clutches (70.1%), as was breeding success (64.9% vs. 54%). Females laying in early spring increased their fitness in rearing more season‐long offspring than did later females. This reproductive strategy seems especially profitable in years with an unusually high rate of nesting failure. The high breeding success (60% of eggs produced fledglings, or 75% excluding the anomalous 1989 data) is supposed to be related to the recent Cetti's warbler breeding range expansion.