This article reviews diagnosis of cerebral amyloid angiopathy (CAA) during life and possible approaches to prevention. A clinical diagnosis of "probable CAA" can be made in patients aged 60 years or older with multiple hemorrhages confined to lobar brain regions and no other cause of hemorrhage. Gradient-echo MRI facilitates diagnosis by showing previous hemorrhages with high sensitivity. This technique can also mark the progression of CAA, as 50% of studied patients developed new petechial hemorrhages during 1.5 years of follow-up. The apolipoprotein E epsilon2 and epsilon4 alleles are associated with increased risk and earlier age of first hemorrhage, but are neither sensitive nor specific for CAA. The major remaining challenges are to develop new markers for the presence of CAA and treatments to block vascular amyloid deposition and vessel breakdown.