EXHIBIT31.2

CERTIFICATION

I, Howard B. Johnson, ChiefFinancial Officer of Vion Pharmaceuticals, Inc., certify that:

1.    I have reviewed this annual report on Form 10-K ofVion Pharmaceuticals, Inc. (the‘‘Registrant’’);

2.    Basedon my knowledge, this annual report does not contain any untruestatement of a material fact or omit to state a material fact necessaryto make the statements made, in light of the circumstances under whichsuch statements were made, not misleading with respect to the periodcovered by this annual report;

3.    Based on myknowledge, the financial statements, and other financial informationincluded in this annual report, fairly present in all material respectsthe financial condition, results of operations and cash flows of theregistrant as of, and for, the periods presented in this annualreport;

4.    The Registrant's other certifyingofficer and I are responsible for establishing and maintainingdisclosure controls and procedures (as defined in Exchange Act Rules13a-15(e) and 15d-15(e)) and internal control over financial reporting(as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for theRegistrant and have:

a)    Designed such disclosurecontrols and procedures, or caused such disclosure controls andprocedures to be designed under our supervision, to ensure thatmaterial information relating to the Registrant, including itsconsolidated subsidiaries, is made known to us by others within thoseentities, particularly during the period in which this annual report isbeing prepared;

b)    Designed such internal controlover financial reporting, or caused such internal control overfinancial reporting to be designed under our supervision, to providereasonable assurance regarding the reliability of financial reportingand the preparation of financial statements for external purposes inaccordance with generally accepted accounting principles;

c)    Evaluated the effectiveness of theRegistrant's disclosure controls and procedures and presented inthis annual report our conclusions about the effectiveness of thedisclosure controls and procedures, as of the end of the period coveredby this annual report based on such evaluation; and

d)    Disclosed in this annual report any change in theRegistrant’s internal control over financial reporting thatoccurred during the Registrant’s most recent fiscal quarter (theRegistrant’s fourth fiscal quarter) that has materiallyaffected, or is reasonably likely to materially affect, theRegistrant’s internal control over financial reporting;

5.    The Registrant's other certifying officer and Ihave disclosed, based on our most recent evaluation of internal controlover financial reporting, to the Registrant's auditors and theaudit committee of Registrant's board of directors (or personsperforming the equivalent functions):

a)    Allsignificant deficiencies and material weaknesses in the design oroperation of internal control over financial reporting which arereasonably likely to adversely affect the Registrant's ability torecord, process, summarize and report financial information; and

b)    Any fraud, whether or not material, that involvesmanagement or other employees who have a significant role in theRegistrant's internal control over financial reporting.

Date: March  16, 2006

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|--------|--|-----------------------------------------|--|--|--|--|
|   |  | /s/ Howard B. Johnson                   |
|   |  | Howard B. JohnsonChief FinancialOfficer |
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