There is growing diversity within the Black population in the U.S., but limited understanding of ethnic and nativity differences in the mental health treatment needs of Black women. This study examined differences in the prevalence of psychiatric disorders, their persistence, and unmet treatment needs among Black women in the U.S. Data were from the National Survey of American Life, a nationally representative survey that assessed lifetime and twelve-month mood, anxiety, and substance use disorders according to the Diagnostic and Statistical Manual of Mental Disorders 4th Edition (DSM-IV) criteria, and mental health service use among those meeting disorder criteria. One in three African American women met criteria for a lifetime disorder, compared to one in three Caribbean women born within the U.S. and one in five Caribbean women born outside the U.S. About half of African American women with a lifetime disorder had a persistent psychiatric disorder, compared to two in five Caribbean women born within the U.S. and two in three Caribbean women born outside the U.S. African Americans had more persisting dysthymia and panic disorder and less persisting social phobia compared to foreign-born Caribbean women. Of the three groups, Caribbean women born within the U.S. were most likely to seek mental health treatment during their lifetime. These results demonstrate, despite a lower prevalence of psychiatric disorders in Black women, that there is a great likelihood their disorders will be marked by persistence and underscores the need for culturally specific treatment approaches. As Black immigrants in the United States are increasing in number, adequate mental health services are needed.