1. A member may not be a homosexual.
2. A member may not be an informant.
3. A member may not be a coward.
4. A member must not raise a hand against another member without sanction.
5. A member must not show disrespect for any member’s family, including sex with another member’s wife or girlfriend.
6. A member must not steal from another member.
7. A member must not interfere with another member’s business activities.
8. A member must not politic against another member or cause dissension within the organization.
9. Membership is for life.
10. Membership mandates assaulting/killing all drop outs.
11. The Mexican Mafia comes first—even before your own family.
That is from the paper Governance and Prison Gangs (HT Marginal Revolution).