Swindon chairman Lee Power says he may be forced to sell players in January if home attendances do not increase.
Town's 1-0 win over promotion rivals Preston on Tuesday attracted a crowd of 6,646 to the County Ground.
"We've based our budget on 7,500, or 7,700 we were getting last season," Power told BBC Wiltshire.
"It's a business and we've lost money tonight. If we continue to do that then I'm going to be left with no choice but to sell one or two of these lads."
Tuesday's home victory moved Swindon up to third in League One, two points behind Preston who occupy the final automatic promotion place.
"It took the gloss off the evening," continued Power. "Yes, some of the results are in and out but we're third and we're playing the team who are second in the league.
"For 6,600 people to turn up is really disappointing. It's something which is a concern to me. We're trying our best off the pitch and the lads are trying on the pitch."
|Swindon's average attendances|
|Statistics from Football League|
Mark Cooper's Swindon finished eighth in the table last term and averaged a league crowd of 8,130 - a drop of 5% from the previous season.
After eight home games of the current campaign, their average attendance is 6,999.
"I'm scratching my head why no-one is coming," continued Power, who took over the club from Jed McCrory 11 months ago.
"I've spent a lot of money to get us where we are and paid off a lot of debt. I've put together a team on the pitch for everyone to be proud of and yet they're still not coming.
"We need the public of Swindon to come and support the team. The away support has been fantastic and the crowd here tonight got behind the lads. We just want a few more people here."