IT integration services are the act of bringing together smaller components into a single system that functions as one. Integration is harder to achieve the greater the number of systems that are involved and companies often choose to have external contractors manage some or all phases of the development of the new system. Challenges to achieving integration mostly have to do with the inherent difficulties in linking a series of diverse existing systems that could be produced by multiple different manufacturers.
Similar: Systems Integration
Note: Integration services are sometimes also referred to as "IT Integration Services" or "Technology Integration Services."