The research was carried out to determine some anthropological tests and their influence on test of 400 meters swimming and to determine differences in the same tests between genders. The sample consisted of 19 male swimmers (10.68 ± 0.48 years, 150.89 ± 7.27 cm and 42.52 ± 7.02 kg) and 12 female swimmers (9.92 ± 0.29 years, 146, 08 ± 7.05 cm and 39.64 ± 9.47 kg). Data processing and statistical analysis in Statistics 13 provided the basic descriptive parameters: Mean, St. dev., Min and Max. The distribution normality was tested by the Kolmogorov-Smirnov test which established normal distribution for all variables, except weight in boys and shoulder flexibility in girls. Pearson's and Kendall Tau correlation coefficients, multiple regression analysis and t-test for independent samples and Mann-Whitney U test were used. The statistically significant difference is defined at p <0.05. The study determined that the anthropometric characteristics that are describing arms span and height statistically significantly affect the score in 400 meter freestyle in boys. No anthropological tests showed a statistically significant effect on the 400 meter freestyle test. In both genders, there was no statistical significance of the effect of used basic motor skills tests on the 400 meters freestyle test. It has been shown that there is a statistically significant difference between some anthropological characteristics between female and male swimmers. (standing horizontal jump, medicine ball throwing from laying down position, and 400 meters freestyle).