It follows a series of incidents in which job candidates have been told they have to hand over passwords as part of the interview process.
"There have been countless examples of employers requiring an applicant to divulge their user name and password as part of the hiring process," said Eliot Engel, one of the Democratic Congressman who introduced SNOPA on Friday.
"Additionally, some universities, and even secondary schools, have required the student either divulge their personal information, or grant the nstitution access to the personal account by ‘friending’ the student."
He said that private social networking content and passwords should have the same protection as email account passwords or banking information.
"These coercive practices are unacceptable, and should be halted," said Mr Engel.
As well as password demands, the Bill would also ban "other means of accessing a private account", which would cover demands for "friend" status.
The Bill is not the first attempt in Congress to outlaw such practices. Last month an amendment to a broad communications Bill was thrown out by Republicans, who argued it was badly drafted but said they would be willing to work on alternatives.
The aims of SNOPA will be welcomed by Facebook itself, which has threatened to sue employers who demand passwords.
"As a user, you shouldn’t be forced to share your private information and communications just to get a job, Facebook's privacy chief Erin Egan said last month.
"We’ll take action to protect the privacy and security of our users, whether by engaging policymakers or, where appropriate, by initiating legal action."
The issue has come to a head after what Facebook described as a "distressing increase"; in cases in the United States over the past few years. For instance, it was widely reported recently that Justin Bassett, a New York City statistician, felt obliged to withdraw from a job application when an interview asked for his login details because "he didn't want to work for a company that would seek such personal information".
The Telegraph uncovered one case of a British job candidate being asked for their Facebook password, and according to legal experts there is nothing to stop UK employers "at least asking the question". Paula Whelan, an employment partner at Shakespeares, said it would be very difficult to prove discrimination if a candidate thought they didn’t get a job because they refused to hand over their loin details.
