Abstract: In the current study, two RT-PCR systems for detection (mono-specific) and typing (duplex) of RSV in clinical samples have been developed and validated. The two assays were exploited for studying the dissemination of RSV infection in Riyadh, Saudi Arabia during the winter season 2007/2008. Furthermore, the effect of certain risk factors, including gender, age and disease form, on extend and impact of the infection was analyzed. Of two hundreds collected samples, 70 (35%) were positive for RSV infection, among which 40 (57.1%) were type A and 30 (42.9%) were type B viruses. This investigation is the first that describes the existence of both RSV subtypes in co-ordinance in Saudi Arabia children, with slight dominance of type A viruses. By analyzing the effect of risk factors on the disease epidemiology we confirmed that males, patients at young age and asthmatics are more susceptible for RSV infection and disease progression.