Source : http://tv.zap2it.com & Nielsen Media Research
Saison 1
Tous les mercredis à 21h
| Date | Episode | Title | Viewers | Share |
| 22/09/2004 | 1 | Pilot (1/2) | 18.653.000 | 20,0% |
| 29/09/2004 | 2 | Pilot (2/2) | 17.004.000 | 17,0% |
| 06/10/2004 | 3 | Tabula rasa | 16.539.000 | 17,0% |
| 13/10/2004 | 4 | Walkabout | 18.157.000 | 17,0% |
| 20/10/2004 | 5 | White rabbit | 16.824.000 | 16,0% |
| 27/10/2004 | 6 | House of the rising sun | 16.834.000 | 16,0% |
| 03/11/2004 | 7 | The moth | 18.729.000 | 17,0% |
| 10/11/2004 | 8 | Cofidence man | 18.435.000 | 17,0% |
| 17/11/2004 | 9 | Solitary | 17.639.000 | 16,0% |
| 01/12/2004 | 10 | Raised by another | 17.150.000 | 17,0% |
| 08/12/2004 | 11 | All the best cowboys have daddy issues | 18.882.000 | 18,0% |
| 05/01/2005 | 12 | Whatever the case may be | 21.590.000 | 19,0% |
| 12/01/2005 | 13 | Hearts and minds | 20.807.000 | 19,0% |
| 19/01/2005 | 14 | Special | 19.694.000 | 18,0% |
| 09/02/2005 | 15 | Homecoming | 19.480.000 | 18,0% |
| 16/02/2005 | 16 | Outlaws | 17.875.000 | 17,0% |
| 23/02/2005 | 17 | … In translation | 19.490.000 | 18,0% |
| 02/03/2005 | 18 | Numbers | 18.851.000 | 18,0% |
| 30/03/2005 | 19 | Deus ex machina | 17.752.000 | 17,0% |
| 06/04/2005 | 20 | Do no harm | 17.123.000 | 17,0% |
| 04/05/2005 | 21 | The greater good | 17.196.000 | 17,0% |
| 11/05/2005 | 22 | Born to run | 17.096.000 | 17,0% |
| 18/05/2005 | 23 | Exodus (1/3) | 18.624.000 | 18,0% |
| 25/05/2005 | 24 | Exodus (2/3) | 20.713.000 | 18,0% |
| 25 | Exodus (3/3) | |||
| Average of the season : | 18.380.708 | 17,5% |
Saison 2
Tous les mercredis à 21h
| Date | Episode | Title | Viewers | Share |
| 21/09/2005 | 1 | Man of science, man of faith | 23.469.000 | 20,0% |
| 28/09/2005 | 2 | Adrift | 23.166.000 | 20,0% |
| 05/10/2005 | 3 | Orientation | 22.377.000 | 20,0% |
| 12/10/2005 | 4 | Everybody hates Hugo | 21.665.000 | 19,0% |
| 19/10/2005 | 5 | … And found | 21.381.000 | 19,0% |
| 09/11/2005 | 6 | Abandonned | 20.012.000 | 18,0% |
| 16/11/2005 | 7 | The other 48 days | 21.868.000 | 19,0% |
| 23/11/2005 | 8 | Collision | 19.293.000 | 17,0% |
| 30/11/2005 | 9 | What Kate did | 21.541.000 | 18,0% |
| 11/01/2006 | 10 | The 23rd psalm | 20.557.000 | 18,0% |
| 18/01/2006 | 11 | The hunting party | 19.126.000 | 17,0% |
| 25/01/2006 | 12 | Fire + Water | 19.100.000 | 16,0% |
| 08/02/2006 | 13 | The long con | 18.737.000 | 16,0% |
| 15/02/2006 | 14 | One of them | 18.199.000 | 16,0% |
| 01/03/2006 | 15 | Maternity leave | 16.432.000 | 15,0% |
| 22/03/2006 | 16 | The whole truth | 16.056.000 | 14,0% |
| 29/03/2006 | 17 | Lockdown | 16.200.000 | 15,0% |
| 05/04/2006 | 18 | Dave | 16.384.000 | 15,0% |
| 12/04/2006 | 19 | S.O.S. | 15.200.000 | 15,0% |
| 03/05/2006 | 20 | Two for the road | 15.559.000 | 14,0% |
| 10/05/2006 | 21 | ? | 15.710.000 | 14,0% |
| 17/05/2006 | 22 | Three minutes | 14.200.000 | 13,0% |
| 24/05/2006 | 23 | Live Together, die alone (1/2) | 17.841.000 | 16,0% |
| 24 | Live Together, die alone (2/2) | |||
| Average of the season : | 18.872.739 | 16,7% |
Saison 3
Mercredi à 21h (pour les épisodes 1 à 6) et 22h (pour le reste)
| Date | Episode | Title | Viewers | Share |
| 04/10/2006 | 1 | A tale of two cities | 18.824.000 | 17,0% |
| 11/10/2006 | 2 | The glass ballerina | 16.892.000 | 15,0% |
| 18/10/2006 | 3 | Further instructions | 16.316.000 | 15,0% |
| 25/10/2006 | 4 | Every man for himself | 17.087.000 | 16,0% |
| 01/11/2006 | 5 | The cost of living | 16.066.000 | 15,0% |
| 08/11/2006 | 6 | I do | 17.149.000 | 15,0% |
| 07/02/2007 | 7 | Not in Portland | 14.490.000 | 14,0% |
| 14/02/2007 | 8 | Flashes before your eyes | 12.770.000 | 12,0% |
| 21/02/2007 | 9 | Stranger in a strange land | 12.890.000 | 13,0% |
| 28/02/2007 | 10 | Tricia Tanaka is dead | 12.770.000 | 13,0% |
| 07/03/2007 | 11 | Enter 77 | 12.340.000 | 13,0% |
| 14/03/2007 | 12 | Par avion | 12.475.000 | 12,0% |
| 21/03/2007 | 13 | The man from Tallahassee | 12.220.000 | 13,0% |
| 28/03/2007 | 14 | Exposé | 11.520.000 | 12,0% |
| 04/04/2007 | 15 | Left behind | 11.658.000 | 12,0% |
| 11/04/2007 | 16 | One of us | 12.090.000 | 12,0% |
| 18/04/2007 | 17 | Catch-22 | 12.075.000 | 12,0% |
| 25/04/2007 | 18 | D.O.C. | 11.820.000 | 12,0% |
| 02/05/2007 | 19 | The brig | 12.100.000 | 12,0% |
| 09/05/2007 | 20 | The man behind the curtain | 12.120.000 | 12,0% |
| 16/05/2007 | 21 | Greatest hits | 12.320.000 | 12,0% |
| 23/05/2007 | 22 | Through the looking glass (1/2) | 13.862.000 | 13,0% |
| 23 | Through the looking glass (2/2) | |||
| Average of the season : | 13.730.591 | 13,3% |
Saison 4
Tous les jeudis à 21h
| Date | Episode | Title | Viewers | Share |
| 31/01/2008 | 1 | The Beginning of the End | 16.137.000 | 14,0% |
| 07/02/2008 | 2 | Confirmed Dead | 15.292.000 | 14,0% |
| 14/02/2008 | 3 | The Economist | 13.757.000 | 13,0% |
| 21/02/2008 | 4 | Eggtown | 13.647.000 | 12,0% |
| 28/02/2008 | 5 | The Constant | 12.893.000 | 12,0% |
| 06/03/2008 | 6 | The Other Woman | 13.008.000 | 12,0% |
| 13/03/2008 | 7 | Ji Yeon | 12.083.000 | 12,0% |
| 20/03/2008 | 8 | Meet Kevin Johnson | 11.461.000 | 11,0% |
| 24/04/2008 | 9 | The Shape of Things to Come | 12.075.000 | 12,0% |
| Average of the season : | 13.372.556 | 12,4% |