The United Nations Institute for Disarmament Research (UNIDIR) and the ISACS Inter-Agency Support Unit, in cooperation with the International Peace Support Training Centre (IPSTC) Humanitarian Peace Support School (HPSS), UNREC and RECSA, conducted the 4th regional training-of-trainers workshop on the ISACS Assessment Tool at the IPSTC/HPSS in Nairobi, Kenya. The workshop trained participants to use the ISACS Assessment Tool to guide their operational work on SALW control in East and West Africa in areas such as stockpile management; marking, record keeping & tracing; and border controls & law enforcement cooperation. Participants became proficient in using the tool to navigate and apply all operational standards from ISACS Series 05.