Objective : To evaluate feasibility, internal consistency, test–retest reliability, and concurrent and discriminative validity of the Infant and Toddler Quality of Life Questionnaire (ITQOL) for parents of pre-school children with 12 scales (103-items) covering physical and psychosocial domains and impact of child health on parents, in comparison with the TNO-AZL Pre-school Children Quality of Life Questionnaire (TAPQOL). ; Methods : Parents of children from a random general population sample (2 months–4 years old; n = 500) and of an outpatient clinic sample of children with respiratory disease (5 months–5 1/2 years old; n = 217) were mailed ITQOL and TAPQOL questionnaires; a retest was sent after two weeks. ; Results : Feasibility: The response was ≥80% with few missing and non-unique ITQOL-answers (25% at maximum score). Internal consistency: All Cronbach’s α >0.70. Test–retest Intraclass Correlation Coefficients (ICCs) were moderate or adequate (≥0.50; p lt; 0.01) for 10 ITQOL-scales. Validity: ITQOL-scales, with a few exceptions, correlated better with predefined parallel TAPQOL scales than with non-parallel scales. Five to eight ITQOL-scales discriminated clearly between children with few and with many parent-reported chronic conditions, between children with and without doctor-diagnosed respiratory disease and with a low and a high parent-reported medical consumption (p