We report herein the results of the cross-cultural adaptation and validation into the Mexican language of the parent's version of two health related quality of life instruments. The Childhood Health Assessment Questionnaire (CHAQ) is a disease specific health instrument that measures functional ability in daily living activities in children with juvenile idiopathic arthritis (JIA). The Child Health Questionnaire (CHQ) is a generic health instrument designed to capture the physical and psychosocial well-being of children independently from the underlying disease. The Mexican CHAQ was already published and therefore it was revalidated while the Mexican CHQ was derived from the European Spanish version with changing of the few words whose use is different in the 2 countries. A total of 182 subjects were enrolled: 89 patients with JIA (26% systemic onset, 47% polyarticular onset, 13.5% extended oligoarticular subtype, and 13.5% persistent oligoarticular subtype) and 93 healthy children. The CHAQ clinically discriminated between healthy subjects and JIA patients, with the systemic onset, and polyarticular onset subtypes having a higher degree of disability, pain, and a lower overall well-being when compared to their healthy peers. Also the CHQ clinically discriminated between healthy subjects and JIA patients, with the systemic onset, and polyarticular onset having a lower physical and psychosocial well-being when compared to their healthy peers. In conclusion the Mexican version of the CHAQ-CHQ is a reliable, and valid tool for the functional, physical and psychosocial assessment of children with JIA.