SummaryA 14½‐year‐old boy with undifferentiated osteochondrodysplasia was described.Shortening of the long bones with metaphyseal flaring were the most important radiographic findings in the newborn period.The dynamic nature of the changes–regression of the metaphyseal flaring and development of other deformities with age (uneven shortening of the long bones, platyspondyly of the thoracic spine, narrowing of the inter‐pedicular distances in the lower thoracic and lumbar spine, hypoplasia of the knee epiphyses with valgus deformity and peculiar shape of pelvis and jaw) have been stressed.This case represents well the unpredictability of bone changes in undifferentiated osteochondrodysplasia of the