SecProbe.io

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December 16, 2005

United States Securities and Exchange Commission
Division of Corporation Finance
450 Fifth St., N.W.
Washington, DC  20549
Attn:    Mr. Jim B. Rosenberg, Sr. Assistant Chief Accountant

Re:      Enzo Biochem, Inc.
         Form 10-K for the FYE 7/31/04, filed 10/14/04
         File no. 001-09974
         COMMENT LETTER DATED DECEMBER 5, 2005

Ladies and Gentlemen:

In response to your  requests  made in a letter dated  December 5, 2005,  we are
pleased to provide you with this additional information and clarification:

Q1.   CONTRACTUAL ALLOWANCE PERCENTAGE
--------------------------------------

In prior  responses  we  incorrectly  used the word  reciprocal.  To compute the
contractual   allowance   percentage,   we  first  determine  the  reimbursement
percentage,  which is based on a rolling  monthly  analysis of the experience of
amounts  approved as reimbursable and ultimately  settled by payers,  versus the
corresponding  gross amount  billed to the  respective  payers.  The  difference
between  the  gross  amount  billed  and  the  reimbursement  percentage  is our
contractual  allowance  percentage  and  represents  the proportion of the gross
billed amounts we do not expect to be reimbursable.

In summary,  the  contractual  allowance  is an estimate  that reduces our gross
amount  billed  to  amounts  that  we  ultimately  expect  to  be  approved  and
reimbursable.  To the extent that reimbursements received are different from the
estimates,  we adjust our  contractual  allowance  in the period  that  approved
settlements  are received.  We adjust the  contractual  allowance  periodically,
based upon our  evaluation  of  historical  settlement  experience  with payers,
industry  reimbursement  trends, and other relevant factors. We believe that our
net revenues for our clinical labs business meet the requirements of SAB 104.

As  with  most  receivables  in  our  industry,  there  exists  some  degree  of
uncertainty about collectibility. While losses as contemplated under FASB #5 may
not be identifiable to a particular receivable amount at a reporting date, based
on  our  historical  experience,   they  do  exist  in  relation  to  our  gross
receivables.   Accordingly,   we  provide  for  estimated   losses  on  our  net
receivables.  The Company  determines the allowance for doubtful  accounts after
the  contractual  allowance  has been  applied to the gross amount  billed.  The
allowance for doubtful accounts percentage is calculated by comparing the sum of
open  accounts  receivable  over  210 days at  balance  sheet  date  and  direct
write-offs

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during a rolling period,  to gross amount billed during the same rolling period.
This doubtful accounts  percentage is applied to open receivables under 210 days
at the balance  sheet date.  The  allowance  for  doubtful  accounts  represents
amounts  that the  Company  does not expect to  collect  after the  Company  has
exhausted its collection procedures.

In summary,  we estimate our allowance  for doubtful  accounts in the period the
related  services  are  billed  and  adjust  in  future  accounting  periods  as
necessary.  We  base  the  estimate  for  the  allowance  on our  evaluation  of
historical collection experience,  the aging profile of accounts receivable, the
historical doubtful account write-off percentages, payer mix, and other relevant
factors.

Q2. TIMING OF ACCOUNTING FOR FINAL SETTLEMENTS
----------------------------------------------

Differences  between the estimated payer approved  reimbursable  settlements and
the  actual  approved  settlements  are  recorded  in  the  period  of  approved
settlement  as  an  adjustment  to  contractual   allowances.   Such  settlement
differences  contribute  to  the  changes  in  our  retrospective  reimbursement
analysis,  described above, and are used to continuously  adjust our contractual
allowance estimate.

Our  clinical  lab  segment's  revenues and accounts  receivable  are net of the
contractual  allowance  and the  allowance  for  doubtful  accounts,  which  are
estimates  based on historical  experience  and judgments  about the future.  We
believe that the use of the rolling monthly analysis experience,  which includes
the impact of final  settlements in the period of settlement,  results in fairly
stated amounts, in all material respects.

Q3. MATERIALITY OF IMPROVEMENT IN ACCOUNTS RECEIVABLE COLLECTION PROCEDURES
---------------------------------------------------------------------------

As noted in our prior response,  the Company's  procedures include the review of
the collectibility of the receivables based on a number of factors,  besides the
period they have been outstanding.  The historical  collection  experience is an
integral part of the  estimation  process  related to the allowance for doubtful
accounts.  The  collectibility  of our  receivables  is  directly  linked to our
overall  billing  and  collection  efforts,  which  include  the  timing  of our
collection  procedures,  most notably  those  related to  obtaining  the correct
information  in order to bill  effectively  for the  services  provided.  During
fiscal  2005,  we put  into  service  at 280  ordering  physicians'  office's  a
sophisticated  information  technology  system (ENZO  DIRECT) to obtain  upfront
billing information directly from the ordering physician at the time of service.
This new system reduced the timing of the  collection  process for inaccurate or
missing  billing  information.  Also in fiscal 2005,  the Company  increased the
billing department's  collection staff, and refocused collection  procedures and
processes.  With the increase in the collection and billing department staff and
the improvement in the information technology system during fiscal 2005, we were
able to shorten the time required to complete our collection procedures.  During
fiscal 2005,  internal  collection  efforts  occurred on a regular basis 90 days
after invoice date using an electronic  mailing process  system.  In fiscal 2004
and prior the  collection  process  occurred 150 days after invoice date using a
manual mailing system.

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This system, increased staff, and the enhanced processes and procedures, allowed
the Company to realize better  collection  rates on our open receivables as well
as exhaust our collection efforts on a more timely basis.  Accordingly,  we were
able to  conclude  that  the  collectibility  of the open  receivables  from all
billing parties that are 210 days and older is doubtful.

As noted  above,  there are a number of factors  that impact the  allowance  for
doubtful  accounts.  The above system,  process and  procedural  changes,  which
constitute  some of the factors,  improved our overall  collections and enhanced
our ability to conclude on collectibility  more timely.  While the above factors
enhanced our estimation process,  the direct effects of such qualitative changes
are not  directly  quantifiable.  Accordingly,  it  would  be  impracticable  to
disclose the impact as recommended under paragraph 33 of APB 20. Improvements or
deterioration  in  collection  rates and the aging of  patient  receivables  are
linked  to  the  overall  quality  of our  billing  and  collection  procedures.
Inherently,  our estimation of net realizable value of patient receivables could
change in a material amount  depending on the  consistency of those efforts.  We
have previously  disclosed in our critical  accounting polices on page 30 of our
fiscal 2005 10K the following:  "The Company believes that the collectibility of
its receivables is directly linked to the quality of its billing  processes." In
future critical accounting policies  discussions,  including our Form 10-Q filed
on December 12, 2005, we will also disclose the following: "Should circumstances
change (e.g. shift in payer mix, decline in economic conditions or deterioration
in aging of patient  receivables),  our  estimates  of net  realizable  value of
receivables could be reduced by a material amount." We believe this enhances the
disclosure and the inherent  risks in our  estimation  process for the allowance
for doubtful accounts.

We  appreciate  your  assistance  in complying  with the  applicable  disclosure
requirements and enhancing the overall disclosure of our filings.

Please contact me if you have additional questions.

Sincerely yours,

s/ Barry W. Weiner
President, Chief Financial Officer and Director

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