Dyslexia is a specific learning disability in reading and writing, which requires adequate early intervention to prevent future school failure. We describe the diagnostic assessment of a 7-year-old boy labelled "dyslexic", the evaluation of his family, social, medical, developmental, and academic status as a preliminary for the design and implementation of a personalized intervention programme. The diagnostic evaluation shows a poor performance in written language, especially in accuracy reading and spelling and reading fluency, making more mistakes in the tests of TALE than normal readers of first level of primary education, and needing consolidate and automate the most of graph-phoneme correspondences. The intervention program continued to be characterized by individual attention, structured and focused on written language, which aims to improve the educational needs that the student has in reading and writing. The teaching and learning experiences that take place following a multisensory approach, which combines the modalities visual, auditory, kinaesthetic, and tactile, in a context of written language as natural and meaningful as possible. After 30 weeks of thrice-weekly sessions, the student has achieved significant improvement in both reading and writing, reducing the number of errors in accuracy and fluency, and improved spelling and joints and fragmentation of words in their written compositions. This progress in the tasks in which previously the child experienced failure demonstrates the effectiveness of the program. (Contains 2 tables and 2 figures.)