A win in either of the two games - away to Honduras on October 10 or at home to Costa Rica four days later - would secure a place in the 2010 finals for the United States.
Cooper (pictured), who last featured in the Gold Cup in July, has made a good start to the season with German second division team 1860 Munich while Conrad, 32, comes back into the squad after Watford centre half Jay DeMerit was ruled out with an eye infection.
The United States are currently top of the six-team CONCACAF qualifying group with 16 points but only four points separate the top four teams with two games remaining.
The top three teams automatically advance to the World Cup finals in South Africa, while the fourth-placed team will participate in a two-leg playoff against the fifth team from South America.
Squad:
Goalkeepers: Brad Guzan (Aston Villa), Tim Howard (Everton)
Defenders: Carlos Bocanegra (Rennes), Jonathan Bornstein (Chivas USA), Steve Cherundolo (Hannover), Jimmy Conrad (Kansas City Wizards), Clarence Goodson (IK Start), Oguchi Onyewu (AC Milan), Jonathan Spector (West Ham)
Midfielders: Michael Bradley (Borussia Moenchengladbach), Ricardo Clark (Houston Dynamo), Clint Dempsey (Fulham), Benny Feilhaber (Aarhus), Stuart Holden (Houston Dynamo), Robbie Rogers (Columbus Crew), Jos Francisco Torres (Pachuca)
Forwards: Jozy Altidore (Hull City), Conor Casey (Colorado Rapids), Brian Ching (Houston Dynamo), Kenny Cooper (1860 Munich), Charlie Davies (Sochaux), Landon Donovan (Los Angeles Galaxy)
