Background: Currently, a few imaging methods are used in CNS diagnostics: computed tomography - CT, magnetic resonance imaging - MRI, and ultrasonography - USG. The ventricular system changes its dimensions with child’s development. Linear indices commonly used in the diagnostics of hydrocephalus do not consider developmental changes of the intracranial fluid spaces. The aim of our work was to identify reference values for selected linear indices in specific age groups. Material/Methods: The material included 507 CT examinations of the head in children of different age and both sexes. There were 381 CT examinations considered as normal and they were used to establish the reference values. They were compared with 126 CTs from the observational zone (3-10 percentile and 90-97 percentile). The children were divided into 7 following age groups: 0-12 months, >12-36 months, >3-6 years, >6-9 years, >9-12 years, >12-15 years, >15-18 years. For every group, the 10th, 25th, 50th, 75th and 90th percentile was calculated. The range between the 10th and the 90th percentile was described as a norm. Results: Reference values for particular indices: Huckman Number from 3.3 to 5.0 cm with correlation coefficient according to age equal to 0.34; Evans’ Index from 0.218 to 0.312 with correlation coefficient of -0.12; Bifrontal Index from 0.265 to 0.380 with correlation coefficient of 0.18; Bicaudate / Frontal Index from 0.212 to 0.524 with correlation coefficient of -0,33; Bicaudate Index from 0.059 to 0.152 with correlation coefficient of -0.26; Bicaudate / Temporal Index from 0.051 to 0.138 with correlation coefficient of 0.32; Schiersmann’s Index from 3.545 to 6.038 with correlation coefficient of 0.42. Conclusions: The intracerebral CSF spaces increased in a non-uniform manner with age. All indices established on the basis of linear parameters were relatively higher in younger children than in the older ones. In proportion to the cranial size, the intracranial fluid spaces decreased according to the age.