Seventeen patients with congenital spondylo-epiphysial dysplasia from six centres in Britain have been investigated and two variants delineated. There is wide clinical and radiological variability in each group with overlap between them, but 12 of the patients had very short stature and grossly disorganised hips with severe coxa vara, and the five remaining patients were less seriously affected with height only a little below the third percentile and only mild coxa vara. Both groups can be diagnosed at birth but the two cannot be differentiated on clinical and radiological grounds until after the age of three to four years when the developing severe coxa vara and difference in stature become apparent. All cases were sporadic with the exception of a concordant twin-pair.