The towel test consists of covering an infant's face with a towel and seeing if he/she can remove it with either arm. In this study it has been used to aid the clinical and electromyographic assessment of 21 infants with obstetric brachial plexus palsy. At 2 to 3 months, none of the 21 infants succeeded in removing the towel, either with their normal or affected arm. At 6 months, all the infants succeeded in removing the towel with their normal arm, but 11 could not with their affected arm, and the same was observed at a further assessment at 9 months. The towel test is a reliable technique for evaluating children with obstetric brachial plexus injuries.