Three children suffering from cystic fibrosis, two girls aged 15 and 7 and one boy aged 18 years, presented growth retardation resulting from increased energy requirements and relative undernourishment. Since oral hyperalimentation was insufficiently efficacious, extra nutrition was administered by tube (at night): a naso-gastric tube, a percutaneous endoscopial gastrostomy catheter or an intragastric tube with a stopper in the skin. All three patients achieved a higher percentile line in the weight/height growth diagram, with stable or improved pulmonary function.