This study examined factors that predict psychological morbidity and screening adherence in first-degree relatives (FDRs) taking part in a familial PSA screening study. Prostate cancer patients (index cases - ICs) who gave consent for their FDRs to be contacted for a familial PSA screening study to contact their FDRs were also asked permission to invite these FDRs into a linked psychosocial study. Participants were assessed on measures of psychological morbidity (including the General Health Questionnaire; Cancer Worry Scale; Health Anxiety Questionnaire; Impact of Events Scale); and perceived benefits and barriers, knowledge; perceived risk/susceptibility; family history; and socio-demographics. Of 255 ICs, 155 (61%) consented to their FDRs being contacted. Of 207 FDRs approached, 128 (62%) consented and completed questionnaires. Multivariate logistic regression revealed that health anxiety, perceived risk and subjective stress predicted higher cancer worry (P = 0.05). Measures of psychological morbidity did not predict screening adherence. Only past screening behaviour reliably predicted adherence to familial screening (P = 0.05). First-degree relatives entering the linked familial PSA screening programme do not, in general, have high levels of psychological morbidity. However, a small number of men exhibited psychological distress.