Exhibit 5.1
                                       
               [LETTERHEAD OF BALLARD SPAHR ANDREWS & INGERSOLL]




                                                                   FILE NUMBER
                                                                     841160


                                       
                                January 26, 1998



Chesapeake Biological Laboratories, Inc.
1111 South Paca Street
Baltimore, Maryland 21230-2591

          Re:  Registration Statement on Form S-8
               
Ladies and Gentlemen:

          We have served as counsel to Chesapeake Biological Laboratories, 
Inc., a Maryland corporation (the "Company"), in connection with its filing 
with the Securities and Exchange Commission (the "Commission") under the 
Securities Act of 1933, as amended (the "Securities Act"), of a Registration 
Statement on Form S-8 (the "Registration Statement") to register up to 
965,275 shares (the "Shares") of Class A Common Stock, $.01 par value per 
share, of the Company (the "Common Stock"), which are issuable upon exercise 
of employee stock options granted under the Company's Second Incentive Stock 
Option Plan and the Company's Third Incentive Stock Option Plan, and granted 
or to be granted under the Company's Fourth Incentive Stock Option Plan 
(collectively, the "Plans"). Capitalized terms used but not defined herein 
shall have the meanings given to them in the Registration Statement.

          In connection with our representation of the Company, and as a 
basis for the opinions hereinafter set forth, we have examined originals, or 
copies certified or otherwise identified to our satisfaction, of the 
following documents (hereinafter collectively referred to as the "Documents"):

          1.   The Registration Statement;

          2.   The Plans;

          3.   The charter of the Company (the "Charter"), certified as of a 
recent date by the State Department of Assessments and Taxation of Maryland 
(the "SDAT"); 



Chesapeake Biological Laboratories, Inc.
January 26, 1998
Page 2


          4.   The Bylaws of the Company (the "Bylaws"), certified as of a 
recent date by its Secretary;

          5.   A certificate as of a recent date of the SDAT as to the good 
standing of the Company;

          6.   Resolutions adopted by the Board of Directors of the Company 
relating to issuance and registration of the Shares pursuant to the Plans 
(the "Resolutions"), certified as of a recent date by the Secretary of the 
Company;

          7.   A form of certificate representing the Shares, certified as of 
a recent date by the Secretary of the Company.

          8.   Such other documents and matters as we have deemed necessary 
or appropriate to express the opinion set forth in this letter, subject to 
the assumptions, limitations and qualifications stated herein.

          In expressing the opinions set forth below, we have assumed, and so 
far as is known to us there are no facts inconsistent with, the following:

          1.   Each of the parties (other than the Company)  executing any of 
the Documents has duly and validly executed and delivered each of the 
Documents to which such party is a signatory, and such party's obligations 
set forth therein are legal, valid and binding and are enforceable in 
accordance with all stated terms.

          2.   Each individual executing any of the Documents on behalf of a 
party (other than the Company) is duly authorized to do so.

          3.   Each individual executing any of the Documents, whether on 
behalf of such individual or another person, is legally competent to do so.
     
          4.   Any Documents submitted to us as originals are authentic.  Any 
Documents submitted to us as certified or photostatic copies conform to the 
original documents.  All signatures on all Documents are genuine.  All public 
records reviewed or relied upon by us or on our behalf are true and complete. 
All statements and information contained in the Documents are true and 
complete. There are no modifications of or amendments to the Documents, and 
there has been no waiver of any of the provisions of the Documents, by action 
or omission of the parties or otherwise.



Chesapeake Biological Laboratories, Inc.
January 26, 1998
Page 3


          The phrase "known to us" is limited to the actual knowledge, 
without independent inquiry, of the lawyers at our firm who have performed 
legal services in connection with the issuance of this opinion for the 
Company.

          Based upon the foregoing, and subject to the assumptions, 
limitations and qualifications stated herein, it is our opinion that:

          1.   The Company is a corporation duly incorporated and validly 
existing under the laws of the State of Maryland and is in good standing with 
the SDAT.  

          2.   The Shares are duly authorized and, when and if delivered 
against payment therefor in accordance with the resolutions of the Board of 
Directors of the Company authorizing their issuance pursuant to the Plans, 
will be (assuming that the sum of (i) all shares of Common Stock issued and 
outstanding on the date hereof, (ii) all shares of Common Stock issued 
between the date hereof and the date on which the Shares are issued (not 
including any Shares) and (iii) the Shares will not exceed the number of 
shares of Common Stock that the Company has authority to issue and assuming 
that the Company is in good standing with the SDAT at any date on which the 
Shares are actually issued) validly issued, fully paid and nonassessable.

          The foregoing opinion is limited to the substantive laws of the 
State of Maryland and we do not express any opinion herein concerning any 
other law.  We express no opinion as to the applicability or effect of any 
state or federal securities laws, including the securities laws of the State 
of Maryland, or as to federal or state laws regarding fraudulent transfers.  
To the extent that any matter as to which our opinion is expressed herein 
would be governed by any jurisdiction other than the State of Maryland, we do 
not express any opinion on such matter.  The opinion expressed herein is 
subject to the effect of judicial decisions which may permit the introduction 
of parol evidence to modify the terms or the interpretation of agreements.

          We assume no obligation to supplement this opinion if any 
applicable law changes after the date hereof or if we become aware of any 
fact that might change the opinion expressed herein after the date hereof.

          This opinion is being furnished to you solely for submission to the 
Commission as an exhibit to the Registration Statement and, accordingly, may 
not be relied upon by, quoted in 



Chesapeake Biological Laboratories, Inc.
January 26, 1998
Page 4


any manner to, or delivered to any other person or entity without, in each
instance, our prior written consent.  

          We hereby consent to the filing of this opinion as an exhibit to 
the Registration Statement and to the use of the name of our firm therein.  
In giving this consent, we do not admit that we are within the category of 
persons whose consent is required by Section 7 of the Securities Act.

                                  Very truly yours,


                                  /s/ Ballard Spahr Andrews & Ingersoll