Highly stable enzyme coaggregates were developed using amyloid fibrils as support materials. Amyloid fibril formation was induced by ionic liquids, and immobilization was done by the coaggregation of enzymes and amyloid fibrils followed by chemical cross-linking. Transmission and scanning electron microscopy studies were carried out to characterize the coaggregates. The amyloid fibril-linked enzymes showed significantly increased stability against various deactivating conditions. In addition, a high level of reusability was clearly observed. This study clearly demonstrated that amyloid fibrils can be used as biomaterials for enzyme immobilization and that amyloid fibril-linked enzyme coaggregates have good potential for industrial applications.