DiPascali, who was chief investment officer (CFO) for Madoff, admitted ten charges - including money laundering, securities fraud and conspiracy - at Manhattan Federal Court.
He confirmed his role in helping Madoff carry out the $65 billion fraud, stating that he recorded "fictitious" securities trades and "lied to the SEC [Securities and Exchange Commission] about the activities of the firm".
According to Reuters, DiPascali faces a maximum possible jail sentence of 20 years, as well as a fine of up to $500,000.
He did not identify other people involved in the fraud in court, but is believed to have provided these names to US prosecutors as part of an attempt to be given a lighter sentence.
Madoff pleaded guilty to the crime in March and is currently serving a 150-year prison sentence in North Carolina.