In 20 children with multiple epiphyseal dysplasia, an objective assessment of epiphyseal size was made to determine its value in early diagnosis of this condition. All had wrist radiographs taken at age less than 15 years, and 16 children had knee radiographs. Before the epiphyses become fully ossified, abnormalities of size and shape may be difficult to assess, but carpal length/width ratios were abnormal in 60%, and distal femoral epiphyseal/metaphyseal ratios were abnormal in 56%. When both measurements were combined, 80% could be classified as abnormal. Objective radiologic assessment of epiphyses is of value in early diagnosis of multiple epiphyseal dysplasia.