Children do not use their voices in an optimal way, appropriate for the healthy development of their voices. Solfeggio, as one of the main subjects in Music schools, is a subject where a music pedagogue can and must be carefully dedicated to the healthy development of children's voices. In order for a Solfeggio teacher or his students to be able for proper usage of their voices and at the same time to develop their vocal potentials, a good knowledge of vocal techniques is required. Special chapters of this thesis are devoted to vocal technique, anatomy of the singing apparatus, the characteristics of the child's voice and their abilities, and the singing and vocal technique in the teaching of the Solfeggio, the influence of vocal techniques on intonation and the methods of intonation. This work was created as a link between the theory taught during the study and the practical experience gained while teaching Solfeggio. This work is a combination of theory taught during the studies and practical experiences during a one-year work at Zlatko Grgošević Music School in Sesvete. The novelty in Solfeggio's teaching is the usage of vocalism or vocal exercises by Nicola Vaccai instead of working on a modulator or "classical" warm up exercises.