Turnover at MCI WorldCom Ireland fell by €8.7 million to €65.7 million in 2003 when compared to the previous 12 months.
The fall in revenues occurred at a time when the firm underwent a major restructuring process under a Chapter 11 bankruptcy.
This process was initiated following the discovery of a massive fraud at the firm's US parent company, which is now called MCI group.
The firm's former chief executive, Bernie Ebbers, is currently standing trial on charges of fraud and the MCI group is now the subject of a bidding war between rival telecoms firms.
Qwest Communications International said late on Thursday that it would submit a new bid to buy MCI . Last week it offered to buy MCI for $8 billion.
However, MCI said earlier this week it had agreed a deal to accept a bid worth $6.7 billion made by the rival firm, Verizon.
Some MCI shareholders have complained this deal undervalues the company.
Meanwhile, the most recent accounts filed by MCI World Com Ireland show it turned a profit of €22.4 million in 2003, a dramatic turnaround from a loss of €116.8 million.
However, the profit figure does not reflect the actual operating performance of the firm because of exceptional contributions made by MCI WorldCom Ireland's subsidiary operations.
For example, the firm's results are boosted from a €23.2 million addition because of the waiver of a provision for intercompany bad debt.
The massive loss posted by MCI WorldCom Ireland a year earlier came from special charges in the accounts and provision for bad debt against monies owed to it by its US parent company, which was in bankruptcy protection following the fraud.
MCI WorldCom employed 102 staff at the start of 2004, compared to 155 a year earlier. This enabled it to cut its wages bill to €6 million in 2003, from €10.4 million in the previous 12 months.