Fast National ratings for Wednesday, July 18, 2012.
 
Led by the Wednesday premiere of "Big Brother," CBS won the night overall, but two hours of "So You Think You Can Dance" led FOX to a win among young viewers despite not winning either of its hours.
 
Among adults 18-49, FOX averaged a 1.8 rating for the night, beating CBS' 1.4 rating and the 1.3 rating for NBC in the key demographic. [Unlike some of its recent demo wins, FOX also won its two-hour block.] ABC averaged a 1.2 rating in the key demo, followed by a 0.3 rating for The CW.
 
Overall, though, CBS came out in first with an average of 5.4 million viewers and a 3.6 rating/6 share for Wednesday primetime. NBC was a close second with a 3.4/6 and 5.22 million viewers, with FOX's 3.1/5 and 5.08 million viewers right behind. ABC's 2.6/4 and 3.91 million viewers finished fourth, while The CW averaged a 0.6/1 and 900,000 viewers.

8 p.m. - CBS started primetime in first with 5.61 million viewers and a 1.9 rating among adults 18-49 for "Big Brother." FOX's "So You Think You Can Dance" was a close second with 5.11 million viewers and a 1.8 key demo rating. There was a drop to the 3.76 million viewers and 0.9 key demo rating for NBC's repeats of "Betty White's Off Their Rockers" and "Up All Night" and to the 3.54 million viewers and 0.8 key demo rating for ABC's "The Middle" and "Suburgatory" repeats. The CW's repeat of "America's Next Top Model" averaged 920,000 viewers and a 0.3 key demo rating.
 
9 p.m. - NBC's "America's Got Talent" averaged 7.48 million viewers and a 1.9 rating among adults 18-49 to win the 9 p.m. hour. CBS' "Criminal Minds" repeat was second overall with 5.07 million viewers and fourth with a 1.5 key demo rating. FOX's second hour of "So You Think You Can Dance" averaged 5.04 million viewers and a 1.8 key demo rating. On ABC, a pair of "Modern Family" repeats averaged 3.98 million viewers and a 1.5 key demo rating. Another "America's Next Top Model" repeat averaged 881,000 viewers and a 0.3 key demo rating for The CW.
 
10 p.m. - CBS moved back into first overall for the 10 p.m. hour with 5.53 million viewers for "CSI: Crime Scene Investigation," which tied for the lead with a 1.15 rating among adults 18-49. NBC's "Law & Order: Special Victims Unit" repeat averaged 4.44 million viewers and also did a 1.15 key demo rating.ABC's "Final Witness" was third with 4.205 million viewers and also averaged a 1.15 key demo rating.
 
All ratings information comes from preliminary Fast National Nielsen data, which includes live and same-day DVR viewing. All numbers are subject to change.