Introduction. Because psychosocial factors are strongly related to IBS symptom severity, there is a need to identify high risk patients before their condition worsens. This study assessed the ability of seven "psychosocial alarm variables" to predict IBS symptom severity. Methods. Eighty two Rome-diagnosed IBS patients (Mean age = 46 yrs, Female = 84%) completed a psychological testing battery that assessed Rome alarm variables: anxiety, suicide ideation, depression, abuse, impaired coping, functional impairment, and pain severity. Results. Pain and functional impairment were highly correlated with IBS symptom severity (IBS symptom severity scale, IBS-SSS); coping and depression were moderately correlated with the IBS-SSS. Regression analyses indicated that psychosocial alarm variables accounted for 46% of the variance in the IBS-SSS. The alarm variable that independently predicted symptom severity was pain severity. Discussion. Data lend empirical validation to the Rome Foundation alarm variables, which appear most useful in flagging patients whose IBS profile is dominated by pain intensity.