Table of Contents

Exhibit99.1

Nalco Holding Company and SubsidiariesSegmentInformation2005 Results Reclassified to Conform with 2006Presentation(Unaudited)

|                                                          |  |                                   |        |                                  |  |                                     |        |                                     |  |                            |        |         |  |        |        |         |  |        |         |         |  |  |
|----------------------------------------------------------|--|-----------------------------------|--------|----------------------------------|--|-------------------------------------|--------|-------------------------------------|--|----------------------------|--------|---------|--|--------|--------|---------|--|--------|---------|---------|--|--|
| (dollarsin millions)                                     |  | Three Monthsended March  31, 2005 |        | Three Monthsended June  30, 2005 |  | Three Monthsended September 30,2005 |        | ThreeMonths ended December  31,2005 |  | Yearended December31, 2005 |
| Industrial and InstitutionalServices                     |  | $                                 | 341.0  |                             |  | $                                   | 377.5  |                                |  | $                          | 379.5  |    |  | $      | 384.1  |    |  | $      | 1,482.1 |    |
| EnergyServices                                           |  |                              | 210.6  |                             |  |                                | 221.5  |                                |  |                       | 223.4  |    |  |   | 244.2  |    |  |   | 899.7   |    |
| PaperServices                                            |  |                              | 170.1  |                             |  |                                | 176.1  |                                |  |                       | 173.9  |    |  |   | 178.0  |    |  |   | 698.1   |    |
| Other                                                    |  |                              | 55.9   |                             |  |                                | 61.2   |                                |  |                       | 58.1   |    |  |   | 57.3   |    |  |   | 232.5   |    |
| NetSales                                                 |  | $                                 | 777.6  |                             |  | $                                   | 836.3  |                                |  | $                          | 834.9  |    |  | $      | 863.6  |    |  | $      | 3,312.4 |    |
| Segmentdirectcontribution:                               |  |                              |   |                             |  |                                |   |                                |  |                       |   |    |  |   |   |    |
| Industrialand InstitutionalServices                      |  | $                                 | 65.5   |                             |  | $                                   | 82.9   |                                |  | $                          | 87.5   |    |  | $      | 86.6   |    |  | $      | 322.5   |    |
| EnergyServices                                           |  |                              | 43.0   |                             |  |                                | 39.7   |                                |  |                       | 42.8   |    |  |   | 47.5   |    |  |   | 173.0   |    |
| PaperServices                                            |  |                              | 30.1   |                             |  |                                | 27.4   |                                |  |                       | 30.8   |    |  |   | 29.7   |    |  |   | 118.0   |    |
| Other                                                    |  |                              | (5.2   | )                           |  |                                | (28.9  | )                              |  |                       | (14.2  | )  |  |   | (17.6  | )  |  |   | (65.9   | )  |
| Capitalchargeelimination                                 |  |                              | 19.8   |                             |  |                                | 19.6   |                                |  |                       | 19.8   |    |  |   | 19.9   |    |  |   | 79.1    |    |
| Totalsegment directcontribution                          |  |                              | 153.2  |                             |  |                                | 140.7  |                                |  |                       | 166.7  |    |  |   | 166.1  |    |  |   | 626.7   |    |
| Expensesnot allocated tosegments:                        |  |                              |   |                             |  |                                |   |                                |  |                       |   |    |  |   |   |    |  |   |    |    |
| Administrativeexpenses                                   |  |                              | 46.5   |                             |  |                                | 47.6   |                                |  |                       | 42.0   |    |  |   | 40.1   |    |  |   | 176.2   |    |
| Amortizationof intangibleassets                          |  |                              | 20.6   |                             |  |                                | 20.5   |                                |  |                       | 20.3   |    |  |   | 20.2   |    |  |   | 81.6    |    |
| Businessoptimizationexpenses                             |  |                              | 0.8    |                             |  |                                | 17.0   |                                |  |                       | 3.5    |    |  |   | 4.3    |    |  |   | 25.6    |    |
| Operatingearnings(loss)                                  |  |                              | 85.3   |                             |  |                                | 55.6   |                                |  |                       | 100.9  |    |  |   | 101.5  |    |  |   | 343.3   |    |
| Otherincome (expense),net                                |  |                              | (3.4   | )                           |  |                                | (0.1   | )                              |  |                       | (0.1   | )  |  |   | 6.7    |    |  |   | 3.1     |    |
| Interestincome                                           |  |                              | 2.1    |                             |  |                                | 2.0    |                                |  |                       | 2.1    |    |  |   | 2.2    |    |  |   | 8.4     |    |
| Interestexpense                                          |  |                              | (62.1  | )                           |  |                                | (64.8  | )                              |  |                       | (65.8  | )  |  |   | (65.3  | )  |  |   | (258.0  | )  |
| Earnings(loss) before income taxes and minorityinterests |  | $                                 | 21.9   |                             |  | $                                   | (7.3   | )                              |  | $                          | 37.1   |    |  | $      | 45.1   |    |  | $      | 96.8    |    |
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