The purpose of this research was to develop and validate tests for the assessment of specific fitness abilities of junior water polo players. In all sports, including water polo, an assessment of motor and functional abilities is required with tests containing movement structures and performance techniques of that specific sport. Applying such tests would give a more accurate picture of the athlete's state of training, which can be used during the selection of talented young water polo players. 72 respondents of junior age from water polo clubs from Croatia and Montenegro participated in the research. The sample of variables was represented by variables of morphological-anthropometric status and variables of sport-specific physical capacities. The reliability of the measuring instruments was observed and descriptive statistical parameters were calculated for all tests. Kolmogorov Smirnov normality test was performed as was the factor analysis using the Guttman-Kaiser criterion with oblique rotation. The analysis revealed good reliability of specific motor and functional variables. The lowest reliability was found in polygon tests, and the highest in swimming tests and tests in which a dynamometer was used. Five latent dimensions were defined, which explain from 11 to 20% of the variability of the applied system of specific motor-functional variables in the sample of respondents.