Background and Purpose —Microvascular changes such as microaneurysms and fibrinoid necrosis have been found in the presence of cerebral amyloid angiopathy (CAA). These CAA-associated microvasculopathies (CAA-AM) may contribute to the development of CAA-associated hemorrhages and/or infarcts, hereafter referred to as “cerebrovascular lesions.” Hereditary cerebral hemorrhage with amyloidosis, Dutch type (HCHWA-D) is an autosomal dominant form of CAA, in which the amyloid angiopathy is pathologically and biochemically similar to sporadic CAA associated with aging and Alzheimer disease. To determine the significance of CAA-AM for CAA-associated cerebrovascular complications, we investigated the association between CAA-AM and cerebrovascular lesions in HCHWA-D patients. Methods —In a previous autopsy study we semiquantitatively scored CAA-AM in 29 HCHWA-D patients. In the present study we reviewed clinical charts and autopsy protocols of these same patients. We investigated whether CAA-AM was associated with age at death, number of cerebrovascular lesions, duration of clinical illness, hypertension, and atherosclerosis. Results —An association was found between CAA-AM and the number of cerebrovascular lesions ( P =0.009). The presence of microaneurysmal degeneration was most strongly associated with the number of cerebrovascular lesions ( P <0.001). In addition, we found an association between atherosclerosis and the CAA-AM score ( P =0.047). Hypertension was not associated with CAA-AM. Conclusions —Our findings support previous reports suggesting an important role of secondary microvascular degenerative changes in CAA-associated cerebrovascular lesions and suggest an aggravating effect of systemic atherosclerosis, but not hypertension, on the evolution of CAA-AM. These findings may be of relevance to understanding cerebrovascular complications of sporadic or Alzheimer disease–associated CAA.