In three children aged 3 to 8 years with large scalp defects temporary expanders of silicone elastomer were inserted under the scalp above the pericranium and under the galea through an incision at the junction of the defect and the normal scalp. Over the following six to eight weeks, the expanders were inflated weekly or semiweekly with injections of saline. During expansion, hair growth continued. When the scalp flap expansion was completed, the scalp margin was advanced. Two of the 3 patients required additional expansion, so a deflated expander was left under the scalp. The entire defect was covered in each case. This technique has wide application for a variety of reconstructive problems.