The first version of the WHO Malaria Microscopy Quality Assurance Manual (2009) was based on recommendations made at a series of informal consultations organized by WHO, particularly a bi-regional meeting of the WHO regional offices for South-East Asia and the Western Pacific in April 2005 in Kuala Lumpur, Malaysia, followed by informal consultations held in March 2006 and February 2008 in Geneva, Switzerland. Subsequently, extensive consultations among international malaria experts led to consensus and preparation of the manual. This second version of the manual is based on the recommendations of experts made at a WHO technical consultation in March 2014 in Geneva, Switzerland. The aim of the meeting was to review the experiences of national malaria control programs (NMCPs), national reference laboratories (NRLs) and technical agencies in using the Manual and country experience in order to improve systems for managing the quality of malaria microscopy.This second version takes into account the many years of experience of several agencies in the various aspects of quality assurance (QA) described in the manual. In particular, the sections on assessment of competence in malaria microscopy are based on use of this method by the WHO regional offices for South-East Asia and the Western Pacific, in collaboration with the WHO Coordinating Centre for Malaria in Australia, and by the WHO Regional Office for Africa in collaboration with Amref Health Africa. The section on setting up and managing an international reference malaria slide bank is based on the work of the WHO Regional Office for the Western Pacific in collaboration with the WHO Coordinating Centre for Malaria Diagnosis in the Philippines. The section on proficiency testing for malaria microscopy is based on work in the WHO Regional Office for Africa in collaboration with the National Institute for Communicable Diseases in South Africa and experience in regional initiatives by Amref Health Africa. The section on slide validation is based on work by Medecins sans Frontieres, and the section on outreach training and supportive supervision (OTSS) is based on work by the President's Malaria Initiative Malaria Care Project, Medical Care Development International and Amref Health Africa.The Manual is designed primarily to assist managers of NMCPs and general laboratory services responsible for malaria control. The information is also applicable to nongovernmental organizations (NGOs) and funding agencies involved in improving quality management systems for malaria microscopy.The Manual is not designed for QA of microscopy in research situations, such as in clinical trials of new drugs and vaccines, or for monitoring parasite drug resistance. It forms part of a series of WHO documents designed to assist countries in improving the quality of malaria diagnosis in clinical settings, including the revised training manuals on Basic Malaria Microscopy (2010) and the Bench Aids for Malaria Microscopy (2010).