High myopia in early childhood is a recognised association of ocular and systemic disease. The aim of this study was to describe the types, pattern and frequency of these associations.All children presenting to two ophthalmology units over 3 years who were found to have high myopia were recruited. High myopia was defined as one or both eyes demonstrating 6 dioptres spherical equivalent or more of myopic refractive error on retinoscopy. We limited the age to less than 10 years old. A retrospective case review was undertaken of the 112 consecutive children who fulfilled the criteria above. The demographic data, source and indication for referral were recorded along with the ocular and systemic findings and diagnosis.Only 9 (8%) of the children had 'simple high myopia' with no associated ocular or systemic associations. In 54% there was an underlying systemic association with or without further ocular problems (e.g. developmental delay, prematurity, Marfan, Stickler, Noonan, Down syndrome) and in the remaining 38% there were further ocular problems associated with the high myopia (e.g. lens subluxation, coloboma, retinal dystrophy, anisometropic amblyopia). A family history of high myopia did not preclude associated abnormality: in 4 cases the diagnosis of a systemic condition in the child led to the identification of the disease in at least one myopic relative. Asian (p < 0.001) and male (p < 0.05) patients were overrepresented in the series.High myopia is strongly associated with systemic and ocular problems; it may be the reason for the child's initial medical referral and an important clue to an underlying systemic or ocular condition. Referrals infrequently originated from community optometrists despite prior attendance. We suggest that all children under 10 years of age with high myopia are referred to a paediatric ophthalmology clinic for review and we propose a structured clinical evaluation in the hospital eye clinic.