Do I have to add back on my Maryland return the contributions that I make to a flexible spending account that I set up with my employer for medical expenses?

No. You do not have to add back the contributions that you make to your employer-maintained health savings account or any other qualified "cafeteria plan" that meets the requirements of Section 125 of the Internal Revenue Code. The contributions remain excluded from your adjusted gross income and your federal adjusted gross income, which is the starting point of your Maryland return.