**Exhibit 31.1**
**CERTIFICATIONS**
I, Rocco B. Commisso, certify that:
(1) I have reviewed this report on Form 10-K of Mediacom Broadband LLC; (2) Based on my knowledge, this report does not contain any untrue statementof a material fact or omit to state a material fact necessary to make thestatements made, in light of the circumstances under which such statementswere made, not misleading with respect to the period covered by thisreport; (3) Based on my knowledge, the financial statements, and other financialinformation included in this report, fairly present in all materialrespects the financial condition, results of operations and cash flows ofthe registrant as of, and for, the periods presented in this report; (4) The registrant’s other certifying officer and I are responsible forestablishing and maintaining disclosure controls and procedures (asdefined in Exchange Act Rules 13a-15(e) and 15d-15(e)) for the registrantand have:
a) Designed such disclosure controls and procedures, or caused suchdisclosure controls and procedures to be designed under oursupervision, to ensure that material information relating to theregistrant, including its consolidated subsidiaries, is made known tous by others within those entities, particularly during the period inwhich this report is being prepared; b) Paragraph omitted pursuant to SEC Release Nos. 33-8238 and34-47986; c) Evaluated the effectiveness of the registrant’s disclosure controlsand procedures and presented in this report our conclusions about theeffectiveness of the disclosure controls and procedures, as of end ofthe period covered by this report based on such evaluation; and d) Disclosed in this report any change in the registrant’s internalcontrol over financial reporting that occurred during the registrant’smost recent fiscal quarter (the registrant’s fourth fiscal quarter inthe case of an annual report) that has materially affected, or isreasonably likely to materially affect, the registrant’s internalcontrol over financial reporting; and
(5) The registrant’s other certifying officer and I have disclosed, based onour most recent evaluation of internal control over financial reporting,to the registrant’s auditors and the audit committee of registrant’s boardof directors (or persons performing the equivalent function):
a) All significant deficiencies and material weaknesses in the designor operation of internal control over financial reporting which arereasonably likely to adversely affect the registrant’s ability torecord, process, summarize and report financial information; b) Any fraud, whether or not material, that involves management orother employees who have a significant role in the registrant’sinternal control over financial reporting.     March 26, 2004 By: /s/ Rocco B. Commisso       **Rocco B. Commisso**      Chief Executive Officer
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**Exhibit 31.1**
I, Mark E. Stephan, certify that:
(1) I have reviewed this report on Form 10-K of Mediacom Broadband LLC; (2) Based on my knowledge, this report does not contain any untrue statementof a material fact or omit to state a material fact necessary to make thestatements made, in light of the circumstances under which such statementswere made, not misleading with respect to the period covered by thisreport; (3) Based on my knowledge, the financial statements, and other financialinformation included in this report, fairly present in all materialrespects the financial condition, results of operations and cash flows ofthe registrant as of, and for, the periods presented in this report; (4) The registrant’s other certifying officer and I are responsible forestablishing and maintaining disclosure controls and procedures (asdefined in Exchange Act Rules 13a-15(e) and 15d-15(e)) for the registrantand have:
a) Designed such disclosure controls and procedures, or caused suchdisclosure controls and procedures to be designed under oursupervision, to ensure that material information relating to theregistrant, including its consolidated subsidiaries, is made known tous by others within those entities, particularly during the period inwhich this report is being prepared; b) Paragraph omitted pursuant to SEC Release Nos. 33-8238 and34-47986; c) Evaluated the effectiveness of the registrant’s disclosure controlsand procedures and presented in this report our conclusions about theeffectiveness of the disclosure controls and procedures, as of end ofthe period covered by this report based on such evaluation; and d) Disclosed in this report any change in the registrant’s internalcontrol over financial reporting that occurred during the registrant’smost recent fiscal quarter (the registrant’s fourth fiscal quarter inthe case of an annual report) that has materially affected, or isreasonably likely to materially affect, the registrant’s internalcontrol over financial reporting; and
(5) The registrant’s other certifying officer and I have disclosed, based onour most recent evaluation of internal control over financial reporting,to the registrant’s auditors and the audit committee of registrant’s boardof directors (or persons performing the equivalent function):
a) All significant deficiencies and material weaknesses in the designor operation of internal control over financial reporting which arereasonably likely to adversely affect the registrant’s ability torecord, process, summarize and report financial information; b) Any fraud, whether or not material, that involves management orother employees who have a significant role in the registrant’sinternal control over financial reporting.     March 26, 2004 By: /s/ Mark E. Stephan       **Mark E. Stephan**      Chief Financial Officer
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