Background & Objective: Poster is a non-projector, visual, graphic and printed medium that is applied in various cases specially in health education. On the other hand, one of the health education experts task is evaluation of educational methods and media. Since few studies were performed on effectiveness of posters on knowledge of people, this study was designed to determine the percentage of people who looked at the posters in health centers and also to determine the level of knowledge attained from these posters located in different places of health centers.

 Methods: This was a semi-experimental study. The population was people who referred to Shahid Gannadi health center. Samples were selected by simple random method. The data were collected by a questionnaire. The posters were fixed in three places during three different stages and the collected data were analyzed.

 Results: The findings showed that from among these subjects, 18.8% in the first stage, 20.8% in the second stage and 61.2% in third stage observed the fixed posters. The probability of the poster to be seen near the doorway and examination room was equal (Odds Ratio=0.9) whereas the probability of the same posters to be seen in waiting hall was 7 times as much as the previously mentioned locations. The ANOVA indicated no significant difference between demographic variables (age, sex, marital status, ets) of study subjects and their knowledge scores.

 Conclusions: The study showed that People paid very little attention to fixed poster. Therefore, regarding the role of posters in increasing the knowledge level, several strategies should be employed to make people pay more attention to these posters. Following the accepted standards in preparation and fixation of posters and preparation of three dimensional boards for the posters in health care centers are suggested.