This is an observational study looking at 1,281,393 men diagnosed with prostate cancer and 842,294 matched prostate cancer-free men. There was an overall increased relative risk of suicide of 2.01 in men diagnosed with prostate cancer compared to those without, in the first year following diagnosis (especially the first six months). Those particularly at risk were aged 75 or older or treated with androgen deprivation therapy, but there was no correlation with marital status, race, disease severity or socioeconomic status. As with all observational studies, association does not equate causation; however, healthcare professionals who may regularly break bad news and look after older men in the first year following their prostate cancer diagnosis should be aware of these findings in order to identify those at risk.