We conducted a descriptive, retrospective, cross-sectional study to assess the core activities and supportive functions of the communicable diseases surveillance system (CDSS) in Khartoum state, Sudan, for the period 2005–2007. This is the first assessment conducted for CDSS in Khartoum state. The CDSS was studied in terms of core activities and supportive functions. We found that knowledge of the system was 100% at all levels. Data reporting was over the recommended standard of 80% at all levels. Data analysis, epidemic preparedness and feedback were below the recommended standard. All assigned CDSS staff members were trained. Lower levels lacked modern technologies for data reporting and analysis. The CDSS system in Khartoum state is centralized; moreover, the system has not been updated, it is poorly documented and has a shortage of staff at lower levels.