The pop group's 1998 double A-side singles 'Tragedy' and 'Heartbeat' top a list of the best-selling tracks to be produced by PWL.
The single has sold over 1.18 million copies in the UK since its release and was also Steps' first ever UK number one.
Kylie Minogue and Jason Donovan are at two with 1988's 'Especially For You', which the duo will perform live at tomorrow's (July 11) Hit Factory concert for the first time in 23 years.
Rick Astley's global hit 'Never Gonna Give You Up' clocks in at three, Dead Or Alive's 'You Spin Me Round' is at four and Minogue's 'I Should Be So Lucky' is at five.
Speaking about the Official Chart Company's Hit Factory list, Pete Waterman said: "Looking at the Official Hit Factory Chart serves as a reminder of all the great artists and singles we've had the pleasure of working on throughout 25 years of PWL – and in the year that the Official Singles Chart itself turns 60, we're proud to have played our own role in its wonderful history.
"On behalf of the artists featured, we look forward to reuniting this week at Hit Factory Live to celebrate!"
The PWL HIt Factory Live concert will take place in London's Hyde Park and feature performances from Steps, Jason Donovan, Kylie Minogue, Rick Astley, 2 Unlimited and Sinitta.
The official Hit Factory Chart Top 10 is as follows:
1. Steps: 'Heartbeat'/'Tragedy'
2. Kylie Minogue and Jason Donovan: 'Especially For You'
3. Rick Astley: 'Never Gonna Give You Up'
4. Dead Or Alive: 'You Spin Me Round (Like A Record)'
5. Kylie Minogue: 'I Should Be So Lucky'
6. Westlife: 'I Have A Dream'/'Seasons In The Sun'
7. Mel and Kim: 'Respectable'
8. 2 Unlimited: 'No Limit'
9. Kylie Minogue: 'Hand On Your Heart'
10. Jason Donovan: 'Too Many Broken Hearts'
Watch the music video for Steps' 'Tragedy' below: