Exhibit 5

                               Quarles & Brady LLP
                            411 East Wisconsin Avenue
                            Milwaukee, WI 53202-4497


                                 March 31, 1999


American Medical Security Group, Inc.
3100 AMS Boulevard
Green Bay, Wisconsin 54313

     Re: American Medical Security Group, Inc. Retirement Savings Plan

Ladies and Gentlemen:

     We are providing this opinion in connection with the Registration Statement
of American  Medical  Security  Group,  Inc.  (the  "Company")  on Form S-8 (the
"Registration  Statement")  to be filed  under the  Securities  Act of 1933,  as
amended (the "Act"),  with respect to the proposed sale of up to 750,000  shares
of Common Stock,  no par value (the  "Shares"),  of the Company  pursuant to the
American Medical Security Group, Inc.  Retirement  Savings Plan, as amended (the
"Plan").

     We have  examined:  (i) the  Registration  Statement;  (ii)  the  Company's
Restated and Amended  Articles of Incorporation  and Bylaws,  each as amended to
date;  (iii)  the  Plan;  (iv)  the  corporate   proceedings   relating  to  the
authorization  for the sale of the  Shares  pursuant  to the Plan;  and (v) such
other documents and records and such matters of law as we have deemed  necessary
in order to render this opinion.

     On the basis of the foregoing, we advise you that, in our opinion:

     1.   The Company is a corporation  duly  incorporated  and validly existing
          under the laws of the State of Wisconsin.

     2.   The Shares to be sold from time to time pursuant to the Plan which are
          original issuance shares,  when issued and paid for as contemplated by
          the Registration Statement and the Plan, will be validly issued, fully
          paid  and  nonassessable  by the  Company,  subject  to  the  personal
          liability   which  may  be   imposed   on   shareholders   by  Section
          180.0622(2)(b)   of  the  Wisconsin   Business   Corporation  Law,  as
          judicially  interpreted,  for debts owing to  employees  for  services
          performed, but not exceeding six months service in any one case.

     We hereby  consent  to the  filing of this  opinion  as an  exhibit  to the
Registration Statement. In giving consent, we do not admit that we are "experts"
within the meaning of Section 11 of the Act, or that we come within the category
of persons whose consent is required by Section 7 of the Act.

                                             Very truly yours,

                                             /s/ Quarles & Brady LLP

                                             QUARLES & BRADY LLP