Given the recent spate of library system vendor acquisitions and consolidations, integrated library system (ILS) migrations have become a hot topic again. Although ILS migrations happen all the time, they tend to be cyclical in nature. Today, people are thinking broadly about what options might be available to them. These include changing vendors, using systems not traditionally associated with a particular library segment, or joining an open source ILS community. In the current marketplace, nothing is beyond consideration. These migrations, however, are distinguished from the efforts that many libraries are undertaking to implement new systems for gaining additional functionality, such as next-generation catalogs. While these next-gen implementations are closely related to the underlying problems and general dissatisfaction with traditional systems, they are distinct from the current ILS migration trend. The primary reason for this is that next-gen system implementations do not, in most cases, replace the library management back-end system, but instead graft new front-end, patron-facing components to the in-place ILS. This article discusses the issues that libraries must consider when migrating to ILS and lists the steps involved in the migration.