Colour Doppler imaging (CDI) potentially provides the facility to differentiate torsion of the testis from inflammatory pathology. Normal control data are required for the purposes of interpretation of abnormal findings. Fifty boys with normal testes were examined by CDI using the Acuson 128XP System. Testicular blood flow was demonstrated in both testes in 58% of boys whilst 34% had no detectable flow. Eight per cent had demonstrable flow demonstrated on one side only. These results indicate that caution should be exercised in diagnosing testicular torsion on colour flow findings alone.