Two patients are reported with the clinical and roentgenographic findings of the Weissenbacher-Zweymuller syndrome. The features are neonatal micrognathia (Pierre Robin syndrome), rhizomelic chondrodysplasia with dumbbell shaped femur and humeri. The bone changes tend to regress and there is normal growth on serial studies. A third case seemed at birth to show similar roentgenographic changes but was dwarfed; serial observations revealed him to be a case of the Kniest syndrome with micrognathia as an added feature. The term "micrognathic dwarfism" suggested by Maroteaux is probably best avoided since it will inevitably include a variety of conditions, only some of which are associated with dwarfism.