Time named Lost the seventh best television series of 2008 and praised the fourth season for "complicat[ing] [Lost's] time-and-space-travel story deliciously".
Don Williams of BuddyTV dubbed "The Beginning of the End" "the most anticipated season premiere of the year" and Michael Ausiello later called the final hour of Lost's fourth season "the most anticipated 60 minutes of television all year." American critics were sent screener DVDs of "The Beginning of the End" and "Confirmed Dead" on January 28, 2008. Metacritic gave the season a Metascore—a weighted average based on the impressions of a select twelve critical reviews—of 87, earning the second highest Metascore in the 2007–2008 television season after the fifth and final season of HBO's The Wire. In a survey conducted by TVWeek of professional critics,
Lost was voted the best show on television in the first half of 2008 "by a wide margin", apparently "crack[ing] the top five on nearly every critic's submission" and receiving "nothing but praise".
The May 7, 2007 announcement of a 2010 series end date and the introduction of flashforwards were received favorably by critics, as were the season's new characters.
The season earned Lost two Television Critics Association Award nominations for "Program of the Year" and "Outstanding Achievement in Drama", although it lost to AMC's Mad Men.
The season has been nominated for a 2008 Writers Guild of America Award in the category of Dramatic Series.
While the first episodes of the season were an improvement over the late episode of the third season, the fourth season generally continued Lost's decline in ratings. The season premiered with eighteen million American viewers, giving Lost its highest ratings in seventeen episodes; however, the size of the audience steadily decreased throughout the season. The eighth episode, which served as the mid-season finale as a result of the writers' strike, brought in thirteen million,
setting a new series low.
The next episode and midseason premiere climbed slightly to fourteen million,
but the episode after that set the current record for lowest-rated episode in the United States with thirteen million people watching.
The finale was seen by fourteen million, reaching the most viewers since the midseason premiere and making it Lost's worst finale yet, ratings-wise.
Despite the decline in viewers, Lost consistently ranked within the top twenty programs of the week with one exception. The finale topped the chart, due to its broadcast being over a week after the official end of the television season. ABC's president Stephen McPherson commented that while he would "love to see the show grow … the reality is that the numbers are pretty good."