The aim of the study was to compare selected anthropometric and physical performance characteristics in prepubertal Budapest girls investigated in 1980 and 2005. For both data collections, the subjects (n=1767 in 1980, and n=1898 in 2005) were volunteer non-athletic girls from the same city districts. Their calendar age ranged between 6.51 and 11.50 years, and the sample size was 5% of the represented populations. Biologically matured girls were excluded from the comparison. Five age groups were formed according to the guidelines of the International Biological Program. Height, body mass and 5 skinfold thicknesses were measured (using Lange caliper). Running speed was assessed by a 30m dash and cardio-respiratory endurance was indicated by 400m run time. Differences between the sample means were tested by a t-test for independent samples at 5% level of random error. According to continuously effecting secular growth changes, differences in height and body mass means were consistently significant, nevertheless the greater body masses were not proportionate to the taller stature. The significantly heavier body of the girls in the second investigation in year 2005 showed a range of 1.83% to 2.10% higher adipose tissue across the age groups [t(df=748) = 4.99, p < .001 for 7-year-olds to t(df=704) = 5.13, p < .001 for 11-year-olds]. Differences in 30m speed performance were not significant, however, the girls averaged 12-13 s longer to complete the 400m run during the second investigation. These differences were significant (p < .001) with t-values ranging from 9.70 to 12.55. In auxology the term secular trend is generally applied to such positive changes that become manifested in faster growth, earlier maturation of children, and taller stature of adults. Among the compared characteristics only the taller height and the heavier body mass in part can be attributed to the secular growth trend. The significantly higher relative body fat content and the lower level of cardio-respiratory endurance reflected a remarkably changed lifestyle. According to Saghi, et al. (2002), Hungarian children's habitual physical activity (including curricular PE classes and participation in organised sport activities out of school) decreased, while time spent in front of video screens (TV, computer) and popularity of fast food restaurants increased; thereby resulting in negative health consequences during the past 25 years. Keyword(s): exercise/fitness, physical activity