OBJECTIVE: The objective of this study was to identify the influence of sucking habits on the occlusal characteristics of the deciduous dentition. METHODS: The initial sample consisted of 86 infants, aged 0 to 3 months. Seven home visits were performed, when and information on breastfeeding practice, nutritive and non-nutritive sucking habits, mouth breathing and dentition development was collected. From the first sample, impressions of the dental arches were obtained from 58 children at the age of 36 months (+2.51SD). Dental casts were obtained and two examiners, trained and calibrated by the Kappa and Pearson Correlation tests, measured several parameters of dental occlusion, such as arch length, depth, and width. RESULTS: The results showed that bottle feeding before 6 months was associated to an increased mandibular intermolar width (p=0.01). Pacifier use before 6 months was statistically associated to a reduction of the maxillary intercanine (p=0.03) and intermolar (p=0.03) width. In addition to these findings, the increased molar depth of the maxillary arch was associated to loss of lip closure before the age of 12 months (p= 0.03). CONCLUSION: According to these results, it could be concluded that sucking habits interfere with the determination of some deciduous occlusal characteristics: pacifier sucking limits lateral-lateral maxillary growth, bottle feeding favors lateral-lateral mandibular growth and open bite development, and the lack of lip closure favors the anteroposterior maxillary growth.