Charlton reported a loss of £690,000 (€1m) in their interim results for the six months ended December 31, 2003.
The loss was caused by a £1m (€1.4m) "charge" relating to one player whose value the club felt had diminished.
Turnover rose 20% to £21.2m (€31.5m) and the club recorded an operating profit of £2.7m (€4m) before player amortisation and player trading.
The results do not cover the sale of Scott Parker to Chelsea for £10m (€14m), which happened in January this year and will create a one-off gain in the end-of-year financial results.
The small loss is in stark contrast to a number of other Premiership clubs' debts and chairman Richard Murray praised the "astute" management of Alan Curbishley and the club's general prudence in financial matters.
"It may not make headlines in the media but our policy of financial responsibility will continue as we progress the development of Charlton Athletic both on and off the field," Murray said.
"The decline in financial liquidity within the football industry has continued.
"For a number of years I have argued the case for clubs to exercise financial responsibility and I think the current debt levels of some clubs remain a cause for concern.
"It is for this reason the Premier League has decided that a nine-point penalty is to be introduced for clubs suffering an insolvency event, a move that we actively supported."
The club could be in an even healthier position this time next year if they manage to secure a place in the Champions League, in addition to the revenue received for the sale of Parker.