​Mail is collected and delivered daily no later than 11:00 a.m. and 3:00 p.m. each business day for all mail stop codes (MSC) in Bethesda, Rockville and Gaithersburg, Maryland.

NIH offices with critical inter-office specials or express mail that cannot wait the next scheduled mail collection/delivery should contact the Mail Customer Service Branch to arrange for a special mail pick-up. Inter-office specials and accountable mail (USPS Express, Registered, Certified and Delivery Confirmation) is delivered to the appropriate individual and/or office within 24-hours of receipt at our main mail center. A signature receipt is necessary for these items​