ABSTRACT.Causes of absence were recorded at two day care centres during a seven‐month period in 1979/80 and a corresponding period in 1987/88, for 82 and 87 children, respectively. During the eight‐year interval absence due to disease decreased from 8.2 % to 5.7 % of total day‐care days. A decrease in epidemic diseases during the eight years was evident. There were no cases of morbilli, parotitis or rubella in 1987/88, following an immunisation programme for these diseases initiated in 1982. An out‐break of varicellae occurred in 1979/80, as compared with only few cases in 1987/88. Respiratory tract infection was the most common type of illness both in 1979/80 and in 1987/88. The mean number of illness episodes of respiratory tract infections per child, aged 5‐6, was significantly higher in the earlier than in the later period, whereas no corresponding difference was evident for the younger age groups. Although, in the meantime parent benefits for home care of sick children had become more generous, attendance at the two day care centres rose from 62 % in 1979/80 to 79 % in 1987/88 of total day‐care days, suggesting a truly decreased morbidity. The carriage rates of pneumococci, Haemophilus influenzae and Branhamella catarrholis decreased with increasing age of the children, and that of beta‐haemolytic streptococci increased; however, the carriage rates during the two periods did not differ significantly. The overall isolation frequencies of these bacteria were 72 %, 43 % and 38 %, respectively, for children aged 1‐2, 3‐4, and 5‐6 years, and