Osteoporosis is a chronic disease that is related with high risk of bone fractures. Together with the use of drugs that slow bone loss or encourage the formation of new bone, diet therapy has a very important role in the osteoporosis treatment. Mediterranean diet with special emphasis on the intake of food that is rich in calcium and vitamin D is the golden standard of nutrition for patients with osteoporosis. The main goal of this research was to assess the nutritional knowledge and eating habits of patients with osteoporosis. Overall one hundred patients participated in this research, 50 from General hospital „Dr. Josip Benčević“ in Slavonski Brod and 50 from Clincal Hospital Centar Rijeka. There were 95 female and 5 male participants. Average age of participants is 62 years, and avarage body mass index 26.4 kg/m2 . Nutritional knowlage of patients with osteoporosis can be reated as insufficient. Most participants do not know that daily needs for calcium of people with osteoporosis is 1200 mg, and for vitamin D 800 to 1000 I.U. Likewise most participants do not know which food is the most important source of calcium. It has been found that almost half of the patients take calcium-containing dietary supplements. In the examined sample, only half of the patients take dietary supplements that contain vitamin D, which is insufficient. This research confirms that certain aspects of diet and behavior such as consumption of carbonated beverages, coffee and tobacco products that have an adverse effect on bone are still overrepresented in patients with osteoporosis. As many as a third of respondents consume carbonated beverages at least several times a week, and coffee on a daily basis. Also, almost a third of respondents consume tobacco products. The task of nutritionists is to participate in designing and implementing not only individual diet therapy for osteoporosis but also educational actions in the wider community with the aim of raising awareness of younger age groups about the importance of a balanced diet, satisfactory calcium intake, optimal vitamin D status and healthy lifestyle to achieve and preserve the optimal bone mass and prevent the development of osteoporosis, a disease that represents a silent epidemic, and which is associated with high mortality and high treatment costs.