Joint Filing Agreement

                                                                       Exhibit 1


                             Joint Filing Agreement

     The undersigned hereby agree that the statement on Schedule 13D with
respect to the Common Stock of Cobalt Group, Inc. is, and any amendment thereto
signed by each of the undersigned shall be, filed on behalf of each undersigned
pursuant to and in accordance with the provisions of 13d-1(k) under the
Securities Exchange Act of 1934, as amended.

Dated: July 7, 2000

                                        WARBURG, ▇▇▇▇▇▇ EQUITY
                                        PARTNERS, L.P.

                                        By: Warburg, ▇▇▇▇▇▇ & Co.,
                                            General Partner

                                        By: /s/ ▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇
                                            ------------------------------
                                            ▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇
                                            Partner


                                        WARBURG, ▇▇▇▇▇▇ & CO.

                                        By: /s/ ▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇
                                            ------------------------------
                                            ▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇
                                            Partner


                                        ▇.▇. ▇▇▇▇▇▇▇, ▇▇▇▇▇▇ & CO., LLC

                                        By: /s/ ▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇
                                            ------------------------------
                                            ▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇
                                            Member