The aim of this study was to assess the periodontal treatment needs of the population under 20 years of age in Spain. 1469 young people, aged 7, 12 and 15-19 years, and representing the urban (60%) and rural (40%) population from Spain were evaluated using the Community Periodontal Index of Treatment Needs (C.P.I.T.N.). In the first age group (7 years), 12% presented calculus or overhanging restorations, and 45% had bleeding upon probing only. In the age group of 12 years the proportion of individuals with calculus, overthanging restorations or moderate pocket depths was 39%, while 38% had gingivitis as their highest treatment need. In the oldest group (15-19 years) the number of subjects with bleeding upon probing decreased to 17%, while the percentage of individuals having moderate pockets, calculus or overhanging restorations increased to 67%. 1% of this youngsters had pockets of 6 mm. or over. At age 7, only 30% had "acceptable gingival health", and no more than 15% of the 18 year-olds reached this condition.