"The objective of this work was to investigate perceptions of dentists' waiting rooms and relate these perceptions with the knowledge of being judging dentists waiting rooms and fear of dental treatment.Context: Waiting rooms are important spaces for medical and dentist personnel for they can influence the patient emotional state and his (her) willingness to submit to treatment. On the other hand, the emotional state of the patient can influence the treatment outcome. In the case of dentists, there is a generalized fear of the dental treatment as it is, generally, associated with great pain. So, waiting rooms must be comfortable and agreeable in order to counteract the anguish related to the proximity of treatment and probably, pain. However, the patient past experiences, anguish and fear of dental procedures are intervene variables capable of influence the patient perceptions of the rooms, in spite of the effort to have pleasant and comfortable rooms and, consequently, influence the relationship between patients and the professionals.Method: Thirty six photographs of 12 waiting rooms of private dentist clinics, arranged in 12 sets of 3 photos of each room, were judged by 152 participants in 15 semantic differentials of rooms attributes. The photographs were shown collectively and the subjects respond, in a formulary, his (her) impressions of the rooms. The attributes used were: "cold/warm", "interesting/boring", heavy/light", "attractive/repulsive", "sad/gay", "significant/trivial", "nice/ugly", "monotonous/variable", "light/dark", "old/modern", "restful/exciting", "simple/sophisticated", "insecure/secure", "neat/messy", "open/closed". These adjectives were chosen in a previous investigation were a series of similar photographs were shown to a group of judges who have to describe attributes of the room."