ln 1976-1997, the breeding biology of the Dipper was studied in the Zasavje region (central Slovenia). 238 nests were found, each of them built in the immediate vicinity of a watercourse, in most cases under a bridge (40% of the nests). Nests are built by females from mid-February to the end of Mareh. They are completed in a week and their average size is 25 by 23 cm. Clutches consist of 3 to 6 eggs (4.7 on average), which measure 26.3 by 18.8 mm on average and weigh 4.6 g. The Dippers breeding in Slovenia have one to two clutches per year. The peak as far as egg-laying for the first clutch is concerned is reached in the second half of Mareh. The eggs are laid only two weeks after the young from the first clutch are fledged, which means that the peak of egg laying in the second nest is reached in the first two thirds of May. The egg-laying procedure (performed only by the female) lasts for 14-15 days. 4.1 young hatch on average and after 3 weeks 4.0 young are fledged. Just hatched young weigh 4 g, just fledged ones some 5.5 g. The growth rate is the highest between their fifth and eleventh days (4.5 g per day). In case of danger the nest is left up to five days earlier. The Dipper is today most endangered by the anthropogenic changes in watercourses and along them.