The breeding biology of the common redstart, Phoenicurus phoenicurus, was studied from 295 nests over 20 years in a nest-box population breeding in managed pine forest in the northeast of the Czech Republic, central Europe. The laying of first eggs lasted from 30 April until 30 June with two distinct peaks in May and June. The estimated proportion of pairs producing two broods per season was 65.4%, the highest estimate in studies of this species. Nest success was only 45.1%, one of the lowest known values. The mean clutch size was 6.30 eggs in assumed first broods and 5.39 eggs in assumed second broods. The production of two broods per season and relatively small clutches is probably a parental adaptation to conditions of frequent nest predation. The two breeding attempts per season could not, however, compensate for the latitudinal differences in clutch size and breeding success, and the seasonal breeding productivity was lower in comparison to populations in the northern area of distribution. At higher air temperatures the breeding started earlier. The air temperature also affected nest success which was highest at mean temperature values and decreased to both low and high temperature extremes. The effects of precipitation, first-egg-laying date, clutch size and year of observation on nest success were not significant.