The HQ was reworded to fit the experiences of prisoners rather than students and 179 male young offenders completed the modified questionnaire (HQ-P) as well as a single-item homesickness measure (SIHM). The HQ-P was internally consistent, and 25 items showed significant differences between homesick and non-homesick groups formed on the basis of the SIHM. There were high positive correlations between the HQ-P total scores and the SIHM for current and initial levels of homesickness. Individuals who experienced initial homesickness tended to remain homesick for some time afterwards. In addition, they were more likely to suffer from anxiety, depression, physical symptoms, and behavioral and cognitive problems. The high levels of homesickness found in this study suggest that homesickness is an important feature of prison life and, as such, should be addressed in relation to prisoners’ welfare and health. Tables, references