This case study reports on the use of intradialytic parenteral nutrition (IDPN) to address severe malnutrition in a 38-year-old woman, redo double lung transplant recipient with a complex medical history including cystic fibrosis and end-stage renal disease (ESRD) on haemodialysis. Gastroparesis and severe postprandial abdominal pain limited oral/enteral nutrition input. The addition of IDPN resulted in a dry weight increase of 13.6% over a 12-month period and an improvement in the patient's malnutrition status from severe (Patient-Generated Subjective Global Assessment (PG SGA) C24) to moderate (PG SGA B7). The patient stated she would recommend IDPN to others in a similar situation. Management of patients with coexisting cystic fibrosis and ESRD with or without haemodialysis requires patient engagement in treatment planning and a multidisciplinary team approach for clinical judgement in the absence of guidelines. As advances in medical care see more patients with these coexisting conditions, IDPN may provide an increasingly useful adjunct therapy.