Is there a size limit for the PDF files submitted using EFS-Web?

Yes, currently the size limit on PDF files is the same size limit for most TXT files. Each file must be smaller than 25 MB. One can upload up to 60 files (if attaching a multi-doc each line of the multi-doc is considered a file) per submission. Please note that only 20 files can be uploaded at a time (i.e. Attach only 20 files each time you press “Upload and Validate”). Sequence listings file size can be up to 100 MB and must be attached, uploaded and validated seperately from all other files.

USPTO FAQ - Questions and Answers (18AUG2008)