The Integrated Disease Surveillance and Response (IDSR) strategy was developed by the Africa Regional Office (AFRO) of the World Health Organisation (WHO) and proposed for adoption by member states in 1998. The goal was to build WHO/AFRO countries' capacity to detect, report and effectively respond to priority infectious diseases. This evaluation focuses on the outcomes in four countries that implemented this strategy. Major successes included: integration of the surveillance function of most of the categorical disease control programmes; implementation of standard surveillance, laboratory and response guidelines; improved timeliness and completeness of surveillance data and increased national-level review and use of surveillance data for response. The most challenging aspects were: strengthening laboratory networks; providing regular feedback and supervision on surveillance and response activities; routine monitoring of IDSR activities and extending the strategy to sub-national levels.