Microsoft Office, the most popular office productivity suite, produces large documents that can result in long download latencies for platforms with limited bandwidth. To reduce latency and improve the user's experience, these documents need to be adapted for transmission on a limited-bandwidth network. To identify opportunities for adaptation, we characterize documents created by three popular applications from the Microsoft Office suite: Word, PowerPoint, and Excel. Our study encompasses over 12,500 documents retrieved from 935 different Web sites. Our main conclusions are: 1) Microsoft Office documents are large and require adaptation on bandwidth-limited clients; 2) embedded objects and images account for the majority of the data in these documents, with image types being the most popular non-text content, suggesting that adaptation efforts should focus on these elements; 3) compression considerably reduces the size of these documents; and 4) the internal structure of these documents (pages, slides, or sheets) can be used to download elements on demand and reduce user-perceived latency.