We describe the La Mascota twinning programme between La Mascota paediatric hospital in Managua, Nicaragua, and hospitals in Monza and Milan, Italy, and Bellinzona, Switzerland. The programme was based on the belief that an attempt to reduce the gap in mortality from cancer in childhood between developed and less developed countries should become an integral part of the care and research activity of a haemato-oncological department of a developed country and not simply an exercise in solidarity. This programme for acute lymphoblastic leukaemia shows that intellectual, organisational, and financial resources can be generated by a twinning programme. What is vital for such programmes is a long-term commitment to a comprehensive and holistic strategy that incorporates supply of drugs, training and supervision of health professionals, and the care of the children and of their parents.