| Date | Time | Comp | Home |
| Away | Venue | TV/Att | Report |
| September 2009 |
| Sat 5 Sep | 5:15 | GP | London Wasps | 26 - 15 | Harlequins | Twickenham | 67,684 | Report |
| Sat 12 Sep | 3:00 | GP | Harlequins | 9 - 15 | Leicester Tigers | Twickenham Stoop | 9,805 | Report |
| Sat 19 Sep | 3:00 | GP | Harlequins | 9 - 22 | Saracens | Twickenham Stoop | 9,209 | Report |
| Fri 25 Sep | 8:00 | GP | Newcastle Falcons | 17 - 17 | Harlequins | Kingston Park | 5,714 | Report |
| October 2009 |
| Sat 3 Oct | 6:05 | GP | Harlequins | 13 - 11 | Bath Rugby | Twickenham Stoop | 11,203 | Report |
| Sat 10 Oct | 1:35 | HC-P5 | Cardiff Blues | 20 - 6 | Harlequins | Cardiff City Stadium | 11,127 | Report |
| Sat 17 Oct | 6:00 | HC-P5 | Harlequins | 19 - 23 | Toulouse | Twickenham Stoop | 12,032 | Report |
| Sat 24 Oct | 3:00 | GP | Worcester Warriors | 22 - 26 | Harlequins | Sixways | 10,010 | Report |
| Sat 31 Oct | 3:00 | GP | Harlequins | 9 - 9 | London Irish | Twickenham Stoop | 14,282 | Report |
| November 2009 |
| Sun 8 Nov | 1:45 | LVC-P2,P3 | Harlequins | 15 - 15 | Scarlets | Twickenham Stoop | 9,653 | Report |
| Sun 15 Nov | 3:00 | LVC-P2,P3 | Newcastle Falcons | 8 - 19 | Harlequins | Kingston Park | 4,650 | Report |
| Sat 21 Nov | 1:00 | GP | Northampton Saints | 26 - 17 | Harlequins | Franklin's Gardens | 13,040 | Report |
| Sat 28 Nov | 3:00 | GP | Harlequins | 35 - 29 | Gloucester Rugby | Twickenham Stoop | 11,854 | Report |
| December 2009 |
| Fri 4 Dec | 7:30 | GP | Leeds Carnegie | 27 - 30 | Harlequins | Headingley Carnegie | 5,090 | Report |
| Sun 13 Dec | 12:45 | HC-P5 | Harlequins | 19 - 29 | Sale Sharks | Twickenham Stoop | 10,533 | Preview |
| Sun 20 Dec | 3:00 | HC-P5 | Sale Sharks | 21 - 17 | Harlequins | Edgeley Park | 7,768 | Report |
| Sun 27 Dec | 4:15 | GP | Harlequins | 20 - 21 | London Wasps | Twickenham | 76,716 | Report |
| January 2010 |
| Fri 1 Jan | 5:30 | GP | Sale Sharks | 21 - 16 | Harlequins | Edgeley Park | 8,172 | Report |
| Sun 17 Jan | 4:00 | HC-P5 | Toulouse | 33 - 21 | Harlequins | Stade Ernest Wallon | 17,535 | Report |
| Sun 24 Jan | 3:00 | HC-P5 | Harlequins | 20 - 45 | Cardiff Blues | Twickenham Stoop | 10,788 | Report |
| Sun 31 Jan | 3:00 | LVC-P2,P3 | London Irish | 13 - 16 | Harlequins | Madejski Stadium | 10,030 | Report |
| February 2010 |
| Sun 7 Feb | 3:00 | LVC-P2,P3 | Harlequins | 29 - 31 | Gloucester Rugby | Twickenham Stoop | 9,732 | Report |
| Sat 13 Feb | 3:00 | GP | Gloucester Rugby | 46 - 6 | Harlequins | Kingsholm | 11,125 | Report |
| Sat 20 Feb | 3:00 | GP | Harlequins | 13 - 6 | Northampton Saints | Twickenham Stoop | 12,935 | Report |
| Sun 28 Feb | 3:00 | GP | London Irish | 29 - 14 | Harlequins | Madejski Stadium | 12,373 | Report |
| March 2010 |
| Sat 6 Mar | 3:00 | GP | Harlequins | 14 - 11 | Worcester Warriors | Twickenham Stoop | 11,274 | Report |
| Sun 21 Mar | 3:30 | LVC-F |
| v |
| Sixways |
|
|
| Sat 27 Mar | 2:15 | GP | Bath Rugby | v | Harlequins | Recreation Ground |
|
|
| April 2010 |
| Sat 3 Apr | 3:00 | GP | Harlequins | v | Newcastle Falcons | Twickenham Stoop |
|
|
| Sat 10 Apr | 2:00 | GP | Harlequins | v | Leeds Carnegie | Twickenham Stoop |
|
|
| Sat 17 Apr | 5:30 | GP | Saracens | v | Harlequins | Wembley Stadium | Sky |
|
| Sat 24 Apr | 3:00 | GP | Leicester Tigers | v | Harlequins | Welford Road |
|
|
| May 2010 |
| 1/2 May |
| HC-SF |
| v |
| TBA |
|
|
| 1/2 May |
| HC-SF |
| v |
| TBA |
|
|
| Sat 8 May | 3:00 | GP | Harlequins | v | Sale Sharks | Twickenham Stoop |
|
|
| 15/16 May |
| GP-SF |
| v |
| TBA |
|
|
| 15/16 May |
| GP-SF |
| v |
| TBA |
|
|
| Sat 22 May | 6:00 | HC-F |
| v |
| Stade de France |
|
|
| Sat 29 May |
| GP-F |
| v |
| Twickenham |
|
|
|