This study examines the relationship between medical and functional severity of disability and levels of self esteem and self concept in 79 young people with spina bifida. Greater feelings of global self worth and of self esteem in physical appearance were associated with greater severity of disability. This was only in part an effect of lower IQ among the most disabled young people. Many of the least disabled had marked impairment of self esteem. Analysis of the impact of individual aspects of disability confirmed the association between increased self esteem in physical appearance and global self worth, and diminished functional ability. Academic self ratings, however, were higher in the less disabled. Hydrocephalus and continence appeared to have minimal effect on self esteem. The relationship between severity of disability in spina bifida and self concept is complex and mediated by a range of factors. It is incorrect to assume that the psychological impact is less in the mildly disabled young person.