[en] Background: Integrated management of childhood illness (IMCI) strategy was developed by the WHO and UNICEF in the mid-1990s as a strategy to reduce under-five mortality. Aimed at countries with mortalities >40/1000 live births, it has been adopted by more than 100 countries. The strategy aims not only to improve case management skills of health workers at the primary level health facilities, but also to strengthen health systems, and to improve home and community practices to prevent common childhood illnesses. The strategy has demonstrated success in enhancing health worker performance, improved quality of clinical care for sick children and low cost care per child correctly managed, improved nutrition status among children, and reduced child mortality where fully implemented. Lessons learnt from IMCI training: IMCI capacity building in both pre-service and in-service training has often been in increasing coverage of trained health workers. In-service training. Major obstacles with in-service training include the cost of a model reliant on centralised, tutor-based training, a shortage of experienced trainers, inadequate supply of training materials, poor follow-up and support supervision, frequent attrition of trained staff, and reaching few private practitioners. Other practical difficulties include releasing essential staff for off-site training, per diem, travel and accommodation costs, and reluctance to apply locally learned skills from centralised courses. To mitigate the challenges, countries responded with a number of strategies to increase coverage. Many countries shortened the IMCI course ranging from 5 to 7 days although the content was largely not reduced, and in some cases, was even increased. A meta-analysis that examined shortened IMCI courses demonstrated that the standard course was superior in terms of health work performance. Pre-service training. This was considered as a feasible solution to increase health system coverage by IMCI trained health workers in a cost effective and sustainable manner and influence practices of health professionals in both the public and private sectors. From inception, many countries responded by introducing pre-service IMCI in the training of nurses, midwives, health officers and medical doctors. The main challenges for pre-service IMCI have been negotiating adequate time and placement into the curriculum, ensuring adequate facilities and organization for clinical sessions, sustaining the supply of teaching materials and coordinating between different academic programmes.