38 CFR § 3.12a - Minimum active-duty service requirement.
(1) The term minimum period of active duty means, for the purposes of this section, the shorter of the following periods.
(i) Twenty-four months of continuous active duty. Non-duty periods that are excludable in determining the Department of Veterans Affairs benefit entitlement (e.g., see § 3.15) are not considered as a break in service for continuity purposes but are to be subtracted from total time served.
(ii) The full period for which a person was called or ordered to active duty.
(2) The term benefit includes a right or privilege but does not include a refund of a participant's contributions under 38 U.S.C. Ch. 32.
(b) Effect on Department of Veterans Affairs benefits. Except as provided in paragraph (d) of this section, a person listed in paragraph (c) of this section who does not complete a minimum period of active duty is not eligible for any benefit under title 38, United States Code or under any law administered by the Department of Veterans Affairs based on that period of active service.
(1) A person who originally enlists (enlisted person only) in a regular component of the Armed Forces after September 7, 1980 (a person who signed a delayed-entry contract with one of the service branches prior to September 8, 1980, and under that contract was assigned to a reserve component until entering on active duty after September 7, 1980, shall be considered to have enlisted on the date the person entered on active duty); and
(2) Any other person (officer as well as enlisted) who enters on active duty after October 16, 1981 and who has not previously completed a continuous period of active duty of at least 24 months or been discharged or released from active duty under 10 U.S.C. 1171 (early out).
(d) Exclusions. The provisions of paragraph (b) of this section are not applicable to the following cases:
(2) To a person who is discharged or released from active duty for a disability adjudged service connected without presumptive provisions of law, or who at time of discharge had such a service-connected disability, shown by official service records, which in medical judgment would have justified a discharge for disability.
(3) To a person with a compensable service-connected disability.
(4) To the provision of a benefit for or in connection with a service-connected disability, condition, or death.
(5) To benefits under chapter 19 of title 38, United States Code.
(e) Dependent or survivor benefits -
(1) General. If a person is, by reason of this section, barred from receiving any benefits under title 38, United States Code (or under any other law administered by the Department of Veterans Affairs based on a period of active duty, the person's dependents or survivors are also barred from receiving benefits based on the same period of active duty.