The aim of this study was to measure the impact of a patient education intervention aimed at increasing dietary intake of calcium and vitamin D in patients currently on androgen deprivation therapy (ADT) for the treatment of prostate cancer. Sixty-one participants attended a one-time dietitian-delivered group education session focusing on diet and lifestyle strategies to reduce the risk of bone loss while on ADT. Dietary intake was assessed using the diet history questionnaire at baseline and again at approximately 1 year post-intervention. Demographics, medical history (including comorbidities), awareness of developing bone loss while on ADT, and information resources utilized were recorded at baseline. Fifty-one participants completed both time points. Over one third of men did not meet minimum current clinical guidelines for calcium or vitamin D intake at baseline. Sixty-three percent of men reported they were aware that osteoporosis was a known side effect of ADT therapy. Only supplemental calcium intake was significantly increased after the intervention. Men aware of their risk of developing bone loss while on ADT reported higher baseline calcium intake (p ≤ 0.05). Men undergoing ADT for less than 1 year at the time of intervention had significantly higher total calcium intake at follow-up compared to men on ADT for longer than 1 year (p = 0.038). Nonsignificant trends indicated that calcium and vitamin D intakes changed to a greater degree in those undergoing ADT for less than 1 year as well. Total calcium and vitamin D did not change significantly as a result of the intervention. Results suggest that promotion of dietary changes may be more effective if delivered closer to the initiation of therapy.