Exhibit12.1

CERTIFICATION

I, Claudio Muñoz,certify that:

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| 1.  | I have reviewed this annualreport on Form  20-F of Compañía deTelecomunicaciones de Chile, S.A.; |

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| 2.  | Based on myknowledge, this report does not contain any untrue statement of amaterial fact or omit to state a material fact necessary to make thestatements made, in light of the circumstances under which suchstatements were made, not misleading with respect to the period coveredby this report; |

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| 3.  | Based on my knowledge, thefinancial statements, and other financial information included in thisreport, fairly present in all material respects the financialcondition, results of operations and cash flows of the company as of,and for, the periods presented in this report; |

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| 4.  | The company's other certifying officer and Iare responsible for establishing and maintaining disclosure controlsand procedures (as defined in Exchange Act Rules 13a-15(e) and15d-15(e)) for the company and have: |

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|  | a)  | Designedsuch disclosure controls and procedures, or caused such disclosurecontrols and procedures to be designed under our supervision, to ensurethat material information relating to the company, including itsconsolidated subsidiaries, is made known to us by others within thoseentities, particularly during the period in which this report is beingprepared; |

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|  | b)  | Evaluated the effectiveness of thecompany's disclosure controls and procedures and presented inthis report our conclusions about the effectiveness of the disclosurecontrols and procedures, as of the end of the period covered by thisreport based on such evaluation; and |

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|  | c)  | Disclosedin this report any change in the company's internal control overfinancial reporting that occurred during the period covered by theannual report that has materially affected, or is reasonably likely tomaterially affect, the company's internal control over financialreporting; and |

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| 5.  | The company's othercertifying officer and I have disclosed, based on our most recentevaluation of internal control over financial reporting, to thecompany's auditors and the audit committee of the company'sboard of directors (or persons performing the equivalentfunctions): |

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|  | a)  | All significant deficiencies andmaterial weaknesses in the design or operation of internal control overfinancial reporting which are reasonably likely to adversely affect thecompany's ability to record, process, summarize and reportfinancial information; and |

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|  | b)  | Any fraud, whetheror not material, that involves management or other employees who have asignificant role in the company's internal control over financialreporting. |

Date: June 29, 2004

|  | By:/s/ Claudio Muñoz Name: Claudio MuñozTitle:     Chief ExecutiveOfficer |
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