But a closer look at the figure reveals a high proportion of users who are choosing not to renew subscriptions and some analysts are dubious whether next year's targets will be met.
Ondigital claims it can be the UK's leading digital television provider, but it is still a long way behind BSkyB's Sky Digital which has over four million users.
And it has ambitious aims to reach the break-even point of two million subscribers by the end of 2002.
"It is not a hope, it is entirely realisable," said Ondigital's chief executive Stuart Prebble.
Subscriber drop-outs
But the company is seeing between 15 and 20% of its existing customers failing to renew subscriptions.
It is this so called "churn rate" that caused investor confidence to waver on Wednesday, despite the successful arrival at the landmark of one million customers.
"It's cheaper to keep a customer than it is to acquire a new one so we work very hard at it," said Mr Prebble, who expects the churn rate to be reduced to 10-12% over the next three years when the customer base stabilises.
Ondigital sales grew by 134,000 in the fourth quarter last year and the sales for the full year were 83% higher than the previous year.
But the full-year figure includes 37,000 customers who have not switched on their service or who received free subscriptions.
Delayed flotation
Ondigital is owned by independent television broadcasters Carlton Communications and Granada Media.
Carlton shares had lost 24 pence by 1330 GMT, while Granada was 10p lower.
And the negative publicity surrounding the churn rate could be one factor delaying Ondigital's long-anticipated flotation.