Micropenis should be diagnosed shortly after birth and differentiated from associated deformities and syndromes. Calling in a paediatric endocrinologist and a geneticist is obligatory. Endocrine treatment should be undertaken in the second and third months (25 mg testosterone enanthate per month) after a positive HCG test. Where there is a negative endocrine response and/or associated sex differentiation derangement, a sex change operation towards female should be discussed with the family at an early stage. Where male determination is already established and the androgen response is poor or absent, the indication is for plastic surgery to elongate the phallus using the Hinman or Johnston technique, performed by an experienced paediatric urologist.