Campaign spokesman Robert Gibbs says the official report for the Chicago Democrat will be filed with the Federal Election Commission next week.
Gibbs says the recent fund-raising effort for the quarter ended June 30 has left state Senator Obama with about $3 million in his campaign fund.
Since becoming a candidate for the seat now held by retiring Republican Senator Peter Fitzgerald, Obama has raised about $10 million.
Obama's Republican opponent, Jack Ryan, withdrew from the race late last month after years'-old allegations made by Ryan's former wife surfaced from their divorce/custody case file.
Republican leaders are expected to name a new nominee as early as next week.