Provided are a method, system, and program for maintaining data in distributed caches. A copy of an object is maintained in at least one cache, wherein multiple caches may have different versions of the object, and wherein the objects are capable of having modifiable data units. Update information is maintained for each object maintained in each cache, wherein the update information for each object in each cache indicates the object, the cache including the object, and indicates whether each data unit in the object was modified. After receiving a modification to a target data unit in one target object in one target cache, the update information for the target object and target cache is updated to indicate that the target data unit is modified, wherein the update information for the target object in any other cache indicates that the target data unit is not modified.