The aim of this study was to compare the administration of the Brazilian version of Early Childhood Oral Health Impact Scale (ECOHIS) questionnaire, applied by face-to-face and telephone format. A randomized sample of 76 parents/guardians of children up to 6 years old was selected in a Pediatric Dentistry Clinic of the Federal University of Santa Maria, Brazil. Patients were randomly selected for 2 different groups, according to administration sequence: F-T (Face-to-face-Telephone) and T-F (Telephone-Face-to-face). Two interviewers administered the ECOHIS questionnaire with 2 week interval between the methods. The reliability between sections of the different methods of administration was assessed by Cronbach's alpha and Intraclass Correlation Coefficient (ICC). There were differences in means of the ECOHIS between face-to-face and telephone methods. However, the value Cronbach's alpha were between 0.94-0.96, and value ICC ranged from 0.91-0.93, proving to be acceptable values. The Bland-Altman plots confirmed the results of reliability tests, supporting the accuracy of the methods. Although there is a slight difference in the scores, the use of both mode of administration of the ECOHIS yields reliable data when single method is used from the beginning to the end of the study. The results provided evidence to use either Face-to-face or Telephone method of administration of the ECOHIS.