The first story in the current series of The Sarah Jane Adventures, Sky, had an official audience of 0.53 million viewers, according to Barb.
Although the figures are slightly down on last year's series opener, The Nightmare Man, which had 0.63 million watching, the two Sarah Jane episodes topped the CBBC chart for the week, with Episode One of Sky getting 0.534 million watching and Episode Two getting 0.532 million.
Third placed Tracy Beaker got 0.407 million watching.
The Series has yet to be shown on the main channel, BBC One and the figures do not include those watching on iPlayer.
The last ever episode of the Sarah Jane Adventures is due to be broadcast later on Tuesday in the UK.