To investigate the knowledge, attitudes and behaviour of Greek adults towards salt as well as their differences with respect to gender, age and level of education.Cross-sectional, observational survey.Voluntary participation to a telephone interview, using a seventeen-item questionnaire.Greek adults aged over 25 years (n 3609), nationally representative according to age, gender and geographical distribution of the Greek population, were interviewed.More women of all age groups compared with men reported adding salt during cooking (P < 0·001), while less reported adding salt on the plate (P < 0·001). Also, more women believed that salt added during cooking was the main source of salt in the diet (P < 0·001). Participants aged 25-34, 35-44 and 45-54 years old had better knowledge of the harmful effects of salt on health compared with the 55+ years age group (P = 0·002, P = 0·001, P < 0·001, respectively); respondents in the aforementioned age groups also knew that children should consume less salt than adults compared with 55+ years age group (P = 0·004, P < 0·001, P < 0·001, respectively). Respondents with secondary and higher educational status were more likely to avoid consumption of processed foods (P < 0·001) and to check the nutrition information on food packaging as compared with respondents having basic education status (P < 0·001).Awareness needs to be raised regarding salt recommendations for adults and children, sources of sodium in the diet and adding less salt during cooking, as well as reading food labels. Future campaigns for salt reduction should consider gender, age and level of education differences regarding knowledge, attitudes and behaviour towards salt.