The purpose of this paper to identify factors which have a bearing on compliance with medical advice in various age groups. The survey was conducted, using the CAWI method, on a representative sample of 1000 respondents who declared having used healthcare services in the previous six months. Control of competences is one of the strongest factors which is common for the oldest and youngest groups. Interestingly, trust in the integrity and honesty of doctors is significant for the youngest patients, i.e., the higher is the level of trust, the lower is the tendency to non-comply. Another type of trust is related to the benevolence of doctors and is significant to patients of the middle age group. Satisfaction is a significant predictor in the two oldest groups of patients. High levels of satisfaction seem to deter people from non-adherence to recommended treatment regimens. The results of the present study provide knowledge about the nature and diversity of factors behind patient compliance in various age groups.