A review of cases of short frenulum (tongue-tie) seen in a recent year at the Lactation Institute and Breastfeeding Clinic provides data about its relationship to sucking and breastfeeding problems such as insufficient infant weight gain and reduced milk supply, sore nipples and repeat bouts of mastitis in the mother. Frenotomy was recommended for ten of 13 babies who appeared to have a short frenulum. Three mothers chose not to hae the frenulum clipped and either gave up breastfeeding or continued to experience problems. Breastfeeding was successfully established by the five healthy babies whose frenulum was clipped. The two babies for whom frenotomy did not completely correct breastfeeding problems had severe birth defects.