It will mark the first time since 1992 the Dolphins have faced the Cowboys in the preseason and the first time since 1983 they have played a preseason game in Dallas.
The other new team on the preseason schedule is Atlanta, which will come to Sun Life Stadium in the third preseason week, Aug. 26-29.
It will be the Falcons' first preseason trip to South Florida since 2005.
The first two preseason opponents are intrastate rivals Tampa Bay and Jacksonville, whom the Dolphins have faced for the last 11 and six preseasons, respectively.
The Dolphins open the preseason at home against Tampa Bay on the weekend on Aug. 12-16 before traveling to Jacksonville the next week.
DOLPHINS' 2010 PRESEASON SCHEDULE
Aug. 12-16 — Tampa Bay at Miami
Aug. 19-23 — Miami at Jacksonville
Aug. 26-29 — Atlanta at Miami
Sept. 2-3 — Miami at Dallas