The deal, unveiled in February and valued at more than $40 billion, would combine the nation's top two cable providers and create an entertainment and Internet behemoth.
Some lawmakers and media watchdogs fear that it would put too much power over cable and the Internet into one company's hands.
Comcast executives have said they expect the deal to be approved by the FCC and the Justice Department.
"Putting these two companies together will not deprive a single consumer in America of a choice he or she has today," Comcast Executive Vice President David L. Cohen said the day the deal was announced.
Comcast will probably file its public interest statement with the FCC on Tuesday. That statement is essentially the company's argument for why the Time Warner Cable acquisition wouldn't harm the public and should be approved.
Cohen, along with Time Warner Cable Chief Financial Officer Artie Minson, will appear before the Judiciary Committee on Wednesday. Also set to appear is Gene Kimmelman, a former Justice Department lawyer and current chief executive of Public Knowledge, a consumer group that has raised concerns about the combination.
If the deal is approved, Comcast would have about a 30% share of the nation's pay-TV households, mostly in the nation's biggest cities including New York, Los Angeles, Chicago, Philadelphia and Washington.
Comcast's potential broadband clout is also of concern to many. The company has noted that in most markets both it and Time Warner Cable serve, there is also competition from phone companies that provide Internet access.
But some lawmakers see this acquisition along with Comcast's 2011 takeover of programming giant
One of the more vocal critics has been Sen.
Comcast has no shortage of executives and lobbyists making its case. Besides Cohen, the company also employs a former FCC commissioner -- Meredith Attwell Baker -- and has a strong presence on Capitol Hill.
Follow Joe Flint on Twitter @JBFlint.