Objectives:To develop a Multiattribute Health Status Classification System (HSCS), to describe the functional health status of 3-year old children. Design:Existing systems (Health Utilities Index, Mark 2 & 3) were revised for application to a preschool (PS) population. The HSCS-PS is comprised of 12 dimensions encompassing a broad range of physical and developmental parameters with between 3 to 5 levels of functional limitations. The dimensions are vision, hearing, speech, mobility, dexterity, self care, emotion, learning and remembering, thinking and problem solving, pain, general health and behaviour. These attributes were selected from a list of 15 attributes considered most relevant by parents and children. A multidisciplinary group of health professionals in pediatrics and 4 directors of follow-up clinics across Canada were also consulted for content validity. Reliability and validity were evaluated by completion of the HSCS-PS questionnaire by parents and health professionals at the clinic visit and again by parents 14 days later. Standardized psychometric tests (Bayley Scales, Vineland, Tellar Visual Acuity) were administered by a“blind” psychometrician. Physical and neurodevelopmental examination was performed by health professionals who were unaware of results of standardized measures. Participants:A prospective cohort of 101 consecutive 3-year old VLBW children attending the follow-up clinic and a sample of convenience of 50 term children. Results:Response rate for test-retest reliability was 95%, with percent agreement between 86% and 100%. Kappa values for various dimensions ranged from 0.38 to 1.00. Inter-rater reliability showed agreement between parents and clinicians ranging from 72 to 100% with clinicians reporting more problems. Agreement was high (>80%) for objective dimensions such as mobility and vision; for subjective dimensions(i.e. self-care, behaviour) agreement ranged from 72 to 80%. Kappa values ranged from 0.30 to 1.00. Conclusions: The HSCS-PS is accepted well by parents and health professionals and takes less than 10 minutes for completion. It is easy to use, widely applicable and provides a functional level in multiple dimensions. Initial assessments of reliability are promising and construct and concurrent validity studies are underway.