The type of files you are importing will have an effect on the speed of the import process. Larger files, like raw sensor files, are normally much larger than JPG files.
But if this is something new, the slowness, and you are using the same camera with the same size files as previously then it's not just the file size.
What type of computer and what operating system are you using.
Thanks for your reply. I am not doing anything different from previous downloads as far as I can tell. I am using a Mac and OS X Yosemite, 10.10.1. Lightroom is unto date. The card reader is Lexar USB 3 and the cards are also Lexar high spend.
If you haven't changed cameras and you're not doing anything different, then perhaps you have a malfunctioning card reader (or some other hardware problem)