Several studies underline the importance of early assessment of the child's ability to analyze the basic operation and not just the deficit areas. The purpose of work is the validation of an observational Scale for the Assessment of Basic Functions (SVFB). 231 children participated (38 with atypical development). The values of Weighed Cohen's Kappa are greater than.75 indicating a good reliability of the observers; the correlative analysis and the Cronbach's Alpha emphasize good internal consistency of the 76 items in the 11 functional areas and there are significant correlations between the SVFB and Brunet-Lézine test stressing good concurrent validity. The SVFB is simple to use and provides immediate environment of the child. The SVFB can be used to draw a base-line in order to forge a path rehabilitative care, or to monitor the therapy.