We examined the records of 147 consecutive patients studied by femoral catheterization to identify factors contributing to angiographic risk in cerebrovascular disease. Cerebral complications occurred in 12.2 percent and were permanent in 5.2 percent. Computer-assisted multivariate analysis of 21 possible risk factors was done. Two of these risk factors correlated strongly with increased risk: number of previous transient ischemic attacks (TIAs) (p < 0.001), and the presence of arterial stenosis of greater than 90 percent (p < 0.03). Risk factors of marginal significance were: diabetes, female sex, and number of selective injections. A discriminant function for estimation of risk was derived: D = [8 × number of TIAs] + [6 × number of arteries catheterized] + [14 if diabetic, 0 if not] + [11 if female, 0 if male]. When D was > 55, 77 percent of patients had a complication. When D was < 55, 98 percent of patients had no complication. Unfortunately, patients in whom the study is most indicated tend to be those at greatest risk.