This study investigated the differences in loneliness, sexual satisfaction, and quality of life among three groups of prison inmates: inmates in a heterosexual romantic relationship with a fellow prisoner, inmates with a partner outside the prison, and inmates without a partner. In-person interviews with 70 male and 70 female inmates from the Topas Penitentiary (Spain) were conducted. These inmates lived in the same facility but in gender-segregated modules. After controlling for age, nationality, total time in prison, actual sentence time served, and estimated time to parole, the results showed a lower level of romantic loneliness, and a higher level of sexual satisfaction and global, psychological, and environment quality of life for the group of inmates with a heterosexual partner inside prison. These findings highlight the positive attributes associated with heterosexual romantic relationships between inmates inside the same prison. (Published Abstract)