The aim of the study was the evaluation of the nutritional habits of the opiates dependent persons before and during methadone maintenance treatment. We examined 48 persons (36 males and 12 females) three times: first time before the methadone treatment, then after 2 months of treatment, and third time after 9 months of treatment. During each examination we performed 24-hour recall four times. Collected data were processed by author's software in order to get information about daily supply of main nutrients (proteins, fat, fatty acids, carbohydrates, dietary fibre, cholesterol), minerals (calcium, iron, phosphorus, zinc, sodium) and vitamins (vitamin A, B1, B2, niacin, C). The changes between the results of following examinations were tested by using the t-Student test. The results were compared with daily norms recommended on the safe level of intake for each age and gender group. In the majority of cases the diet of examined persons was quite reach in protein, but we noticed too low daily intake of fats, essential fatty acids, some minerals (calcium, iron, magnesium, zinc) and vitamins B1, B2 and C. After 2 months of methadone treatment the daily intake of fats, saturated fatty acids, essential fatty acids, cholesterol, dietary fibre, some minerals and vitamins decreased in men group, but in the last examination we noticed renewed growth in quantity of those nutrients in daily diet of examined persons. We did not observe it in the group of women.