Background: Poliomyelitis is a highly infectious viral disease that affects children below the age of 15 years which is transmitted via the fecal-oral route from person to person. One in every 200 infections leads to irreversible paralysis, usually in the legs. Polio is preventable by immunization and earmarked by the World Health Organization for eradication. Sierra Leone is working toward certification of Poliomyelitis-free status. A suspected case of Polio is any child under 15 years of age with acute flaccid paralysis (AFP) or any person of any age with paralytic illness which the clinician suspects poliomyelitis involvement and a confirmed case is any suspected case from which the wild polio virus is isolated. The AFP surveillance system in Sierra Leone was evaluated to determine if the system was meeting its set objectives and to assess the system's attributes. Methods & Materials: We used guidelines developed by Centres for Disease Control and Prevention, Atlanta. We reviewed surveillance records and analysed data sets on AFP from 2005 to 2012 from the National Surveillance Unit. We also interviewed stakeholders at all levels. Results: From 2005-2012, 8 wild polio virus case were identified in the country; in 2009 six wild polio cases were identified; Bo, Moyamba, Port-Loko and Western Area (Rural) had one case each whilst Kambia had 2. In 2010 and 2011; Western Area (Rural) identified a case. The non-polio AFP rate increased from 2.4 to 6.2 cases per100,000 children below 15 years from a target of 2 cases per 100,000 children below 15 years. The AFP surveillance system is integrated with other priority diseases and has a clear case definition and external laboratory support. The system is simple, flexible, sensitive, specific, stable and well represented. Incompleteness, poor data management and analysis at the district levels are the weaknesses. Vices are poor feedback, inadequate personnel and logistics. Conclusion: The AFP surveillance system meets set objectives but needs improvement in efficiency in logistics planning, data management, data quality including completeness and analysis. Feedback from national levels to the districts and below should be monitored including timely laboratory results.