Microsoft expects to sell more than one million Zune music players by the end of June 2007.
The Zune comes in three colours - brown, black and white
The player has had a soft debut in the music player market in the US, with mixed reviews from consumers and critics alike.
A report from market research firm NPD Group showed that Zune's share of the US digital music player market fell to 2% and fifth place recently.
Great rival Apple has sold more than 70 million iPods in the last five years.
A spokeswoman for Microsoft said the firm was not concerned that Zune player sales had dropped each week since its debut.
"While this is expected, our focus is less on week over week numbers, and more on the incremental sales that are leading to overall growth of the category," she said in a statement.
Many analysts see Microsoft's Zune player as a first step in a long-term plan to compete with Apple, reflected in the US-only release of the player.
The 30-gigabyte Zune costs $249 (£130) and comes with wireless technology that allows users to beam photos and songs to one another.
Microsoft has said it plans to invest hundreds of millions of dollars to develop and market the Zune, and has acknowledged that the investment may take years to bear fruit.
The company has taken a similar approach with its Xbox games division, growing sales and credibility in the market while initially having limited success against competitors.